What Australian Non-Residents Must Do When the ATO Issues a Default Assessment After Years of Non-Lodgment – And How ODIN Tax Responds

A default assessment is not a warning. It is the ATO’s formal, legally binding calculation of what it believes you owe – issued when you have failed to lodge a tax return and the ATO has decided to stop waiting. For Australian non-residents who have not filed a non-resident tax return in Australia for several years, the moment a default assessment lands is one of the most consequential in their tax life. The penalties that attach to it, the interest accruing daily, and the compressed window to respond make immediate, informed action the only sensible path. This article explains exactly what a default assessment means for non-residents, what the ATO can and typically does charge, and how a structured response can materially change the outcome.

What Exactly Is an ATO Default Assessment?

A default assessment is the ATO’s statutory power to assess your tax liability without a return from you. When lodgment obligations go unmet, the ATO does not simply wait indefinitely. It constructs an estimate of your income and issues a formal assessment based on that estimate – which becomes legally valid and payable as if you had lodged a return yourself [lawpath.com.au].

The critical misunderstanding many non-residents hold is that no return means no obligation. That is incorrect. The obligation to lodge exists independently of whether you submitted anything. The ATO’s estimate will typically be unfavourable, often drawing on third-party data such as bank reporting, property sales data, and employer records to produce a figure that may significantly exceed your actual liability.

What Penalties and Charges Actually Apply?

The financial consequences of a default assessment compound in three distinct layers, and understanding each one matters for calculating the real cost of inaction.

The 1 July 2025 change to GIC deductibility is particularly significant for non-residents with property income. Previously, the interest component of a growing ATO debt could reduce your net Australian taxable income. That offset no longer exists for charges accruing from that date, making delay materially more expensive than it was in prior years [securedlending.com.au].

Why Non-Residents Face a More Complex Response Than Australian Residents?

Building on the penalty framework above, the harder question for non-residents is not just “how do I respond?” but “what do I actually owe once residency status, treaties, and withholding are properly applied?” This is where the default assessment process diverges sharply from the experience of an Australian resident.

Several non-resident-specific factors must be resolved before you can accurately know what the corrected liability should be:

• Tax residency determination: The ATO applies four tests – the Resides Test, the Domicile Test, the 183-Day Test, and the Commonwealth Superannuation Test. Your residency classification determines every rate, threshold, and offset that applies to your assessment.
• No 50% CGT discount: Non-residents do not access the 50% general CGT discount available to Australian residents. If the ATO’s default assessment includes a property sale, its calculation of capital gain may be correct on this point even if residents assume otherwise.
• Foreign resident CGT withholding: Under the foreign resident CGT withholding rules, buyers of Australian property from foreign residents are required to withhold a percentage of the purchase price and remit it to the ATO at settlement. If this was withheld on a property you sold but never declared, it may have already reduced your actual net liability – but only if properly credited against your return [ausbusinessregister.com.au].
• Double Tax Agreement (DTA) offsets: Australia has tax treaties with over 40 countries. Income already taxed in your country of residence may qualify for a Foreign Income Tax Offset, reducing your Australian liability – but only if claimed correctly in a lodged return.
• HECS/HELP debt: Non-residents earning above the worldwide income threshold are required to make HELP repayments. This is a separate obligation that may or may not appear in a default assessment.

A generalist accountant unfamiliar with these mechanics will often prepare the response incorrectly, leaving money unclaimed or inadvertently confirming a higher liability than necessary.

What Should You Actually Do After Receiving a Default Assessment?

Stepping back from the technical detail, the procedural question is straightforward even when the underlying numbers are not. The process below reflects the ATO’s own published guidance and the established practice for resolving these situations [waterhousetaxlawyers.com.au].

1. Do not ignore it. A default assessment is immediately payable. Silence confirms it and the penalties continue to accrue.
2. Engage a registered tax agent immediately. An agent can communicate with the ATO on your behalf, request lodgment deferrals where relevant, and manage penalty remission applications.
3. Lodge all outstanding returns. This is the primary mechanism to dispute the ATO’s estimate. When actual returns are lodged, the ATO replaces its default figure with the correctly calculated liability [waterhousetaxlawyers.com.au].
4. Negotiate a payment plan if the resulting liability is unmanageable. The ATO will typically work with taxpayers who engage proactively rather than those who continue to go silent.

How ODIN Tax Responds to Default Assessment Cases

A related but distinct question is what this process looks like when handled by a specialist rather than addressed alone or through a generalist practice. ODIN Tax’s response to default assessment cases for non-residents follows a structured sequence that accounts for the non-resident-specific complexity described above.

As a Registered Australian Tax Agent with a practice built exclusively around Australian expats and non-residents, ODIN Tax’s process involves:

• Reviewing the default assessment and identifying where the ATO’s estimate differs from actual income, gains, and entitlements.
• Determining the correct tax residency status across the relevant years – this alone frequently changes the liability calculation.
• Preparing and lodging all outstanding non-resident tax returns in Australia across multiple prior years, with correct treatment of rental income, property sales, foreign income tax offsets, and foreign resident CGT withholding credits.
• Submitting a penalty remission request with a documented case for ATO discretion where the client’s circumstances support it.
• Where relevant, coordinating with ODIN’s mortgage and property teams so that any ATO resolution does not inadvertently affect a property transaction already in progress.

The ATO’s compliance focus on non-residents has intensified through 2025 and into 2026, with increased data matching from foreign financial institutions and property registries [securedlending.com.au]. The window for proactive self-correction – before the ATO acts first – continues to narrow.

Frequently Asked Questions

Technically you can object, but lodging the actual overdue return is the most effective and accepted mechanism to replace the ATO’s estimate with the correct figure. An objection alone without the underlying return data is rarely successful [waterhousetaxlawyers.com.au].

The ATO has discretion to remit penalties for taxpayers who engage proactively, provide a credible explanation, and cooperate fully. Voluntary disclosure before the ATO contacts you generally produces a better result than responding after a default assessment is issued. No outcome is guaranteed.

If foreign resident CGT withholding was collected by the buyer’s conveyancer at settlement and remitted to the ATO, it functions as a prepayment of your CGT liability. It must be correctly credited in your return to reduce the net amount payable. If no return has been lodged, that credit sits unclaimed.

ODIN Tax prepares backdated non-resident tax returns in Australia across multiple prior years. The number of years depends on your specific lodgment history and when your Australian tax obligations began.

No. GIC incurred on or after 1 July 2025 is no longer tax-deductible. This materially increases the real cost of carrying an unresolved ATO debt compared to prior years.

A nil return may still need to be lodged to formally close out the obligation for that year. Your registered tax agent can confirm which years require a return and which may be excluded from the lodgment obligation.

Yes. As a Registered Australian Tax Agent, ODIN Tax can act as your authorised representative with the ATO, correspond on your behalf, and manage the entire lodgment and penalty negotiation process remotely.

References

1. Australian Tax Compliance for Foreign Companies 2026-27 (ausbusinessregister.com.au)
2. ATO Crackdowns in 2025/2026 | Secured Lending (securedlending.com.au)
3. What’s a Default Assessment? – Lawpath (lawpath.com.au)
4. Don’t get caught out by an ATO default assessment – Waterhouse Lawyers (waterhousetaxlawyers.com.au)