Most investors approach refinancing as a numbers exercise. You compare your current rate against what’s available, do a rough calculation on the monthly savings, and decide whether it’s worth the hassle. But for investment property owners, that framing misses the point entirely — and in some cases, it leads to decisions that quietly erode tax deductions for years.
The reality is that refinancing an investment property is not simply a rate decision. It’s a structuring decision. Get the structure right, and you can lower your repayments, release equity for your next purchase, and keep every dollar of interest working in your favour at tax time. Get it wrong — by mixing purposes, misusing redraw, or consolidating the wrong debts — and you can contaminate a previously clean investment loan and create an apportionment headache that your accountant will be dealing with indefinitely.
This article is written for Australian property investors who want to refinance intelligently — not just cheaply. It covers how the process works, what the ATO actually looks at, which loan structures protect your deductibility, and the real scenarios where investors come unstuck.
If you’re at the point of weighing up whether to refinance, or you’re looking at your first investment loan and want to get the structure right from the start, speaking with a broker who specialises in investor lending makes a measurable difference. Understanding how to refinance your mortgage as an investor involves different considerations than refinancing a home loan — from how lenders assess rental income to how the loan is structured across splits. And if you’re still building the portfolio, getting the right investment loan in place from day one avoids many of the structuring problems this article covers.
Why investors refinance in the first place
Before getting into the tax mechanics, it helps to understand the range of legitimate reasons investors refinance. The decision is rarely about one thing.
The most common motivation is rate reduction. After a period of rate rises or simply sitting with the same lender for too long, many investors find they’re paying significantly above the market rate. Even a 0.4% reduction on a $600,000 investment loan saves around $2,400 a year before tax — and because investment loan interest is deductible, the after-tax saving is less than that, but it’s still meaningful.
Equity release is the second major driver. If your investment property has grown in value, refinancing gives you access to that equity without selling the asset. That released capital is typically used as a deposit on the next property or to fund renovations on the existing one. This is how many investors with a single property eventually build a portfolio — not through savings, but through leverage against capital growth.
Resetting the interest-only period is another common goal. Many investment loans are structured on a five-year interest-only term. When that term expires, the loan converts to principal and interest, which increases repayments significantly. Refinancing to a new lender — or renegotiating with the existing one — can reset the interest-only clock, which protects cash flow without requiring the borrower to sell.
Some investors also refinance to improve the loan’s features. A better offset account, more flexible redraw, a lower annual package fee, or access to a construction facility for future development can all justify the switch. And for investors managing multiple properties, refinancing can also be about separating security — moving away from cross-collateralisation toward standalone loans — which gives much more flexibility when selling or refinancing individual assets later.
How the refinancing process works in Australia
The mechanics of investment property refinancing are broadly similar to owner-occupier refinancing, but with a few additional layers that investors need to understand.
The process typically starts with a valuation. The new lender will order an upfront valuation to establish the current market value and determine how much they’re willing to lend. For investment properties, some lenders apply a slight discount to their assessment relative to residential valuations — particularly for units, regional properties, or higher-density buildings — so the outcome isn’t always as generous as the owner expects.
Serviceability is assessed differently for investors too. Most lenders will shade rental income — typically counting only 75% to 80% of the gross rent — to account for vacancy and management costs. Existing investment loan repayments will often be assessed at a stressed rate rather than the actual rate. This means a borrower who services their loans comfortably in real life may not pass every lender’s calculator, which is why using a broker who understands investor serviceability across multiple lenders makes a significant difference.
Once the valuation and serviceability clear, the application goes through standard credit assessment — income verification, liability checks, credit history — before the new lender issues a formal approval. Settlement involves the new lender paying out the existing loan, discharge documents being registered, and any new security arrangements being put in place. The whole process typically takes four to eight weeks depending on lender turnaround and valuation complexity.
The tax rule that investors cannot afford to ignore
This is where investment property refinancing becomes meaningfully different from refinancing a home loan — and where most generic content on the topic falls short.
The ATO does not determine deductibility based on the security property. It determines deductibility based on the use of the borrowed funds. This distinction sounds technical, but its practical implications are enormous.
If you refinance your investment property and the new loan simply replaces the old one — same purpose, same outstanding balance — the interest remains fully deductible. The security is an investment property, the debt was originally incurred to acquire that investment property, and nothing about the fundamental purpose has changed. Straightforward.
But the moment borrowed funds are used for something else, the picture changes. If the refinance involves releasing equity and that equity is used to fund a holiday, a car, private school fees, or any other personal expense, the interest on that portion of the loan is not deductible. It doesn’t matter that the loan is secured against an investment property. The ATO follows the money, not the mortgage.
When borrowed funds are split between investment and personal use — which is common in refinances where equity is partly reinvested and partly accessed for personal reasons — the interest must be apportioned. That means your accountant needs accurate records of how much was used for each purpose, and that proportion determines what can and cannot be claimed each year.
The legal basis for this is well established through the ATO’s guidance on interest deductibility and the principle that interest is deductible under section 8-1 of the Income Tax Assessment Act 1997 where it relates to borrowings made to produce assessable income. Investors who don’t understand this often end up overclaiming — and the correction process is neither quick nor cheap.
Common tax traps when refinancing an investment property
Mixing personal and investment debt in one loan
This is the most common mistake, and it often happens innocently. An investor refinances and takes out a slightly larger loan than the current balance — say $420,000 on a $400,000 investment loan — and uses the extra $20,000 to pay off a credit card. That credit card balance was private debt. The moment it’s absorbed into the investment loan, the loan becomes mixed-purpose, and interest on the $20,000 portion becomes non-deductible.
The problem compounds over time. As repayments are made, the mixed proportion doesn’t automatically resolve itself. The ATO requires that you track the apportionment carefully — and if repayments aren’t allocated correctly between the two purposes, the contamination can persist or even worsen.
Using redraw and losing track of purpose
Redraw is a particularly dangerous feature when it comes to investment loan deductibility. Here’s how the trap works: an investor makes extra repayments on their investment loan, reducing the balance. They later redraw those funds to pay for something personal — a family holiday, furniture for their home. At that point, the redrawn amount changes purpose. It was repaid from investment-related cash flows, but it’s now been used for private spending. The interest on the redrawn portion loses its deductibility.
Redraw is different from an offset account in a critical way. Funds in an offset account are never actually part of the loan — they sit alongside it and reduce the interest calculation without being drawn into the loan balance. When you withdraw from an offset account, you’re withdrawing your own money. When you redraw from an investment loan, you are re-borrowing, and the purpose of that re-borrowing determines deductibility.
For investment loans, offset accounts are almost always preferable to redraw facilities for this reason. The tax treatment is cleaner, the records are simpler, and there’s no risk of accidentally re-borrowing for the wrong purpose.
Assuming property type determines deductibility
This misconception catches a lot of investors out. The logic goes: “The property is an investment, so all interest on the loan is deductible.” That’s not how it works. An investment property can have non-deductible debt attached to it if some of the borrowed money was used for personal purposes. Conversely, an owner-occupier might have a portion of their mortgage that’s deductible if they’ve used borrowed funds to acquire income-producing assets — through debt recycling, for example.
The security is almost irrelevant from the ATO’s perspective. Purpose is everything.
Consolidating private debt into the investment loan
Debt consolidation is often marketed as a benefit of refinancing — and in some circumstances, it can reduce overall repayments and simplify the picture. But consolidating private debt (car loans, personal loans, credit cards) into an investment property loan is a deductibility trap. The interest on the private debt was never deductible. Once it’s absorbed into the investment loan, it doesn’t become deductible. What it does is increase the investment loan balance, potentially improve cash flow short-term, and create a mixed-purpose loan that requires ongoing apportionment.
In most cases, a broker who understands investor tax requirements will steer you away from this approach — or at minimum flag the tax consequences before you proceed.
Poor record-keeping after the refinance
Even investors who structure everything correctly at the time of refinancing can create problems by failing to document what they did and why. If the loan is later reviewed by the ATO, or if you switch accountants and they need to understand the loan history, the absence of records becomes a serious issue. A written file note at the time of refinancing — setting out the original loan balance, the refinanced amount, the purpose of any additional funds drawn, and how the loan is split — takes twenty minutes and protects you from significant uncertainty down the track.
Tax opportunities when refinancing is structured correctly
Refinancing to fund another investment property
This is one of the cleanest tax outcomes possible from an investment refinance. If you refinance and release equity, and that equity is used as a deposit or purchase contribution for another income-producing property, the interest on the released amount is fully deductible. The purpose of the borrowed funds is investment — acquiring an asset that produces assessable income — and the ATO’s tracing principle works in your favour.
The key is to keep the equity release in a separate loan split from day one. Don’t let it blend into the existing investment loan balance. A standalone split — say, a $100,000 equity release loan separate from the $400,000 original refinanced loan — creates a clean paper trail where the entire $100,000 split is traceable to investment use.
Refinancing to fund deductible property improvements
If the released equity is used for genuine improvements to the rental property — not the family home, not personal spending, but the income-producing property itself — the interest is deductible, and the improvements themselves may create capital works deductions over time. Renovating a kitchen, replacing a roof, or adding a bathroom to the rental all qualify as investment-related expenditure.
The distinction the ATO draws is between repairs (deductible immediately) and improvements (deductible over time as capital works). Refinancing to fund a genuine improvement is not a tax trap — it’s an opportunity — but again, the loan split should clearly earmark those funds separately from any non-deductible borrowings.
Borrowing expense deductions
When you refinance, you incur fees — application fees, valuation fees, legal costs, discharge fees from the old lender. These borrowing expenses are themselves deductible, but not in the year you pay them. For investment loans, borrowing expenses above $100 are generally deducted over the lesser of five years or the loan term. This is often overlooked at tax time. Keep a record of what you paid to set up the new loan, give it to your accountant, and make sure it appears in your return each year until fully claimed.
Loan structure choices that protect investors
The right loan structure at the time of refinancing will determine how clean or complicated your tax position is for the life of the loan. These are the decisions worth spending time on with both your broker and accountant before you sign anything.
Separate loan splits for separate purposes are non-negotiable when equity is being released for different uses. If you’re refinancing a $500,000 investment loan and releasing $80,000 equity — $50,000 for a deposit on the next property and $30,000 to renovate your own home — those three amounts should be in three separate loan splits. The first ($500,000) is a clean investment refinance. The second ($50,000) is a deductible equity release. The third ($30,000) is personal and non-deductible. Keeping them separate makes the tax treatment clear without any apportionment required.
Offset accounts versus redraw was covered above in the context of tax traps, but it’s worth restating as a positive structural choice. For any investment loan, an offset account is almost always the preferred feature over redraw. It gives the same interest reduction benefit while maintaining the integrity of the loan balance for deductibility purposes. If you’re choosing between lenders and one offers only redraw while the other offers a proper offset, that should factor into your decision — especially if you anticipate making extra repayments and wanting to access them later.
Interest-only versus principal and interest is partly a cash flow decision and partly a tax one. Investors who are in the growth phase of their portfolio typically prefer interest-only because it maximises deductible interest and minimises non-deductible cash tied up in loan repayment. As you pay down principal, you’re reducing a deductible expense and building equity — which is fine once the portfolio is stabilising, but not always the optimal structure when you’re still acquiring. Your accountant can model the actual tax impact of each option based on your income and existing portfolio structure.
Real investor scenarios
Abstract principles are easy to nod along to and harder to act on. These scenarios illustrate how the decisions described above play out in practice.
Sarah owns a two-bedroom unit in Melbourne that she’s held for six years. The property has grown from $480,000 to approximately $680,000. Her existing loan sits at $395,000 and is fully investment-purpose with clean records. She wants to release equity to fund a deposit on a second investment property interstate. She refinances to $544,000 — 80% of the $680,000 valuation — structured as two splits: $395,000 (the original balance) and $149,000 (the equity release). Both splits are investment-purpose, both attract deductible interest, and the split structure makes the purpose of each portion unambiguous. This is a textbook structuring outcome.
Marcus owns an investment property in Brisbane and also has $28,000 remaining on a personal car loan at a higher rate. His lender offers to consolidate everything into the investment refinance to simplify his finances. He accepts without asking a broker or accountant. His investment loan is now contaminated — the $28,000 is embedded in the loan with no clean split, interest apportionment is required going forward, and his accountant needs to track the non-deductible proportion for as long as that debt remains. The monthly saving on the car loan rate does not come close to justifying the ongoing tax administration and the permanent reduction in deductible interest.
James has been making extra repayments on his investment loan for two years. His balance is $30,000 lower than the scheduled amount. His refrigerator dies, then his hot water system at home fails, and he decides to redraw $18,000 from the investment loan to cover the costs. Both items are for his private residence. The $18,000 redraw is now personal in purpose — non-deductible — and his investment loan balance needs to be tracked as a mixed-purpose loan. Had he kept those funds in an offset account rather than making additional loan repayments, he could have withdrawn the same amount without any impact on deductibility.
Priya’s interest-only period on her investment property expires in three months. Her lender tells her the loan will convert to principal and interest, increasing her monthly repayment by $800. She approaches a broker, refinances to a new lender with a competitive variable rate and a fresh five-year interest-only term, and reduces her repayment to below the original IO figure. Her total repayments drop, her deductible interest is maintained, and she uses the additional monthly cash flow to contribute to her offset account on the property she lives in — which reduces the non-deductible debt on her home faster.
Refinancing costs: what investors are actually paying
The conversation around refinancing tends to focus on the saving — the rate reduction, the lower monthly repayment — without adequately accounting for what the switch actually costs. For investment properties, these costs are real and should be factored into any break-even calculation.
Discharge fees from the existing lender typically run between $150 and $400 depending on the lender. Application or establishment fees at the new lender can range from nil on some variable rate products to $600–$900 on packaged loans. Valuation fees, where not waived, are usually $200–$400 for a standard residential investment property. If there’s a fixed rate component being broken, break costs can run into the thousands depending on how far rates have moved since the loan was fixed and how much time remains on the fixed term — this cost should always be confirmed in writing before proceeding.
Some lenders offer cashback incentives to attract refinancers, which can partially offset these upfront costs. But a $3,000 cashback paired with an interest rate that’s 0.2% higher than the best available is likely to cost more than it saves over a two or three year period. Evaluate the total cost of the loan — rate, fees, features — rather than the headline cashback amount.
A simple break-even calculation: if the refinance costs you $2,500 all in, and the monthly saving is $200, the break-even point is around thirteen months. If you plan to hold the loan and the property beyond that, the refinance makes financial sense. If there’s any likelihood of selling or refinancing again within that window, the case is weaker.
Questions to ask before you refinance
Before committing to a refinance, these questions — asked of your broker and accountant in combination — will help ensure the outcome is what you intend.
Ask your broker: What is the comparison rate, not just the advertised rate? What fees will I incur on both the exit and the entry? If I’m releasing equity, how should the loan be structured to protect deductibility? Which lenders will assess my rental income most favourably for serviceability? Is cross-collateralisation involved, and is there an alternative?
Ask your accountant: What is the current purpose breakdown of my existing loan? If I release equity for this purpose, will it be fully deductible? How should I document this at the time of settlement? What borrowing expenses will I need to claim, and over what period? How does switching from principal and interest to interest-only affect my taxable income this year?
These two conversations, had before you sign anything, are the single most effective way to ensure the refinance delivers what you’re expecting — financially and at tax time.
Mistakes investors make when refinancing
To consolidate the practical guidance above, these are the mistakes worth actively avoiding.
Refinancing without a clear purpose for any equity released — and assuming it can be sorted out later — creates immediate problems that are difficult to unwind. Decide before the application what the released funds will be used for, and structure the loan accordingly.
Choosing a lender solely on interest rate without considering offset account quality, redraw terms, or annual fees is a common error. Over a five-year period, a loan with a genuinely functional offset account can outperform a lower-rate loan without one, depending on how much you keep in the offset.
Signing off on a single large loan where a split structure would have served you better. The paperwork is marginally more complex with splits, but the tax clarity is worth it — particularly when one portion of the borrowing is for investment and another is personal.
Waiting too long to involve your accountant. Many investors brief their accountant after the refinance has settled and the structure is locked in. Getting accountant input before the application — particularly on how any equity release should be categorised — avoids the situation where the loan is settled in a way that creates ongoing tax complications.
Frequently Asked Questions
Is the interest still deductible if I refinance an investment property?
Yes, provided the refinanced loan is used for the same purpose as the original — acquiring and holding the investment property. The refinance itself doesn’t change the deductibility of the interest. What can change deductibility is if additional funds are drawn at the time of refinancing and those funds are used for non-investment purposes.
Can I release equity from an investment property without creating a tax problem?
Yes, if the released equity is used for an investment purpose — such as a deposit on another income-producing property, or renovations to the rental property itself. Set the release up in a separate loan split from the start to make tracing straightforward.
What happens if I use part of the refinanced funds for personal expenses?
The interest on that portion of the loan becomes non-deductible. If it’s blended into the investment loan without a separate split, you’ll need to apportion the interest each year and your accountant will need to track the private proportion for as long as it exists in the loan.
Does refinancing trigger capital gains tax?
No. Refinancing is not a disposal of the asset — you still own the property — so no CGT event occurs at refinancing. CGT becomes relevant when you sell, or in certain other events like transferring ownership.
Are the costs of refinancing tax deductible?
Yes, on an investment property, borrowing expenses (application fees, legal costs, valuation fees, mortgage stamp duty where applicable) are deductible over five years or the loan term, whichever is shorter. Discharge fees from the old lender are also deductible as borrowing expenses. Keep all documentation.
Is an offset account better than redraw for an investment loan?
In almost every case, yes. With an offset, you’re parking your own money alongside the loan — when you withdraw it, there’s no change to the loan balance or its purpose. With redraw, you’re re-borrowing, and if the re-borrowed funds are used for personal purposes, that portion becomes non-deductible. Offset accounts provide the same cash flow benefit with cleaner tax treatment.
Should I split the loan when refinancing for multiple purposes?
Yes. Any time refinancing involves funds that will be used for different purposes — part for the existing investment loan, part released for another investment, part for personal use — each purpose should be in its own split. It’s the most effective way to maintain clean deductibility records and avoid the ongoing complexity of apportionment.
Can I refinance to buy another investment property?
Yes, and the interest on the equity release portion used as a deposit or purchase contribution will be deductible because it’s being used to acquire an income-producing asset. Speak to your broker about structuring the release as a standalone split.
If I use refinanced funds to renovate the rental property, is the interest deductible?
Yes. Using borrowed funds for capital improvements or repairs to an income-producing property is an investment use, so the interest is deductible. The renovation costs themselves may be deductible immediately (if they’re repairs) or over time (if they’re capital improvements). Your accountant can advise on the distinction.
Can I consolidate personal debt into my investment refinance?
Technically you can, but it’s generally a poor idea from a tax perspective. Personal debt absorbed into an investment loan doesn’t become deductible — it simply contaminates the investment loan and creates an apportionment requirement. The short-term cash flow improvement rarely justifies the long-term tax complexity.
Will switching to interest-only affect my tax position?
Switching to interest-only increases the amount of deductible interest you pay each year, which can reduce your taxable income from the investment property. It does not change what’s deductible — it changes the quantum. For investors in higher tax brackets with negatively geared properties, interest-only repayments can have a meaningful annual tax impact.
Can I still refinance if serviceability is tight but the property has grown in value?
Possibly, but it depends on the lender. Equity alone doesn’t guarantee a refinance — lenders still assess income serviceability. Some lenders are more generous in how they treat rental income or assess existing investment loan repayments. A broker who regularly works with investors can identify lenders whose policies suit your income profile.
How do I know if the refinance savings outweigh the fees?
Calculate total upfront costs (discharge fee, application fee, valuation, legal) and divide by the monthly saving on repayments. The result is your break-even period in months. If you plan to hold the loan longer than that break-even point, the refinance is financially justified on numbers alone — setting aside the structural and tax benefits, which may also be significant.
The bottom line
Refinancing an investment property can achieve a lot — lower costs, better cash flow, equity release, portfolio growth, improved loan features. But the difference between a refinance that delivers all of that and one that quietly creates tax problems for years is almost entirely in how the loan is structured at the time of settlement.
The core principle to take away is simple: in Australia, interest deductibility follows the use of borrowed funds, not the property used as security. Once you understand that, every other decision in this article flows logically from it — why splits matter, why offset beats redraw, why mixing personal debt into an investment loan is problematic, and why a few hours spent with both your broker and accountant before signing saves far more than it costs.
Investors who treat refinancing as a structuring decision — not just a rate decision — consistently get better long-term outcomes. The rate difference between lenders is often marginal. The difference between a clean, well-structured investment loan and a contaminated one can affect your tax position for as long as you hold the property.