How to Amend a Tax Return in Australia: A Step-by-Step Guide

Lodging a tax return and then realising something is wrong is more common than most people think. A missed deduction, an income source that slipped through, or a figure entered incorrectly - these happen every year across thousands of returns. The good news is that a lodged return is not final. You can change it, and in many cases the change results in a larger refund than you originally received.

Can You Change a Tax Return After Lodging?

Yes. The ATO allows taxpayers to request an amendment to a lodged income tax return for a defined period after the original assessment was issued. You are not locked into the figures you submitted, provided you act withintime.

An amendment is a formal request to change specific items in your original return. It produces a revised Notice of Assessment that either increases your refund, reduces a tax bill, or in cases where an error worked in your favour, results in an amount owing.

An amendment is not in itself a red flag or an admission of wrongdoing - it is simply the mechanism for correcting the record.

Common Reasons People Amend Their Tax Return

Returns get amended for two broad categories of reason: errors that need correcting, and entitlements that were missed. Both are legitimate reasons to amend, and both are fully supported by H&R Block's Second Look service.
  

Errors That Need Correcting

• Forgetting to declare income from a secondary employer, bank interest, share dividends, rental property, or gig economy work
• Entering an incorrect amount in any field of the original return
• Reporting income that you subsequently discovered was incorrectly characterised, such as a genuine redundancy payment that was partially tax-free
• Claiming a deduction in the wrong category or under the wrong method

 

Entitlements That Were Missed

• Work-related deductions that were not claimed: occupation-specific expenses, home office costs, vehicle use, professional memberships, or self-education
• Investment deductions overlooked on rental properties: depreciation, capital works, interest, or management fees
• Charitable donation deductions not included
• Tax offsets not applied, such as the Low Income Tax Offset or seniors and pensioners offset
• Franking credits on share dividends that were not included in the refundable credits section

 
People who did not use a tax professional when lodging are often surprised to discover legitimate deductions they were entitled to but never claimed. An amendment in these cases puts money back in the taxpayer's pocket, not more into the ATO's.
 

How Long Do You Have to Amend a Tax Return in Australia?

The time limit for amending a tax return depends on your circumstances:
 

Taxpayer Type	Time Limit to Amend
Individuals and trusts (most cases)	Two years from the date the original Notice of Assessment was issued
Sole traders (from the 2024-25 income year onwards)	Four years from the date the original Notice of Assessment was issued
Sole traders (income years before 2024-25)	Two years - the four-year extension does not apply retrospectively
Outside the standard time limit	An out-of-time amendment cannot be requested, however an objection to the assessment can be lodged. Objections generally have the same time limits as amendments, but the ATO has the discretion to treat the objection as if it was lodged on time.

  
The time limit runs from the date on your Notice of Assessment, not from the date you lodged the return. If your original return took several weeks to process, the amendment window begins from when the assessment was issued, not when you submitted.

If you are outside the standard time limit, all is not necessarily lost. You are able to lodge an objection to an assessment and, unlike amendments, the ATO can exercise discretion to allow an out-of-time objection in certain circumstances, and having a registered tax professional lodge the objection on your behalf produces a better outcome than attempting it independently. When lodging an objection, all supporting documents will need to be provided.

Act before the ATO contacts you: If you have identified an error in a lodged return, amending before the ATO raises the issue with you is consistently treated more favourably than an error the ATO finds through its own data-matching program. Voluntary disclosure demonstrates good faith and typically results in lower or no penalties compared to errors identified by the ATO independently.
 

How to Amend Your Tax Return with H&R Block

H&R Block Second Look Assessment

H&R Block offers a free review of tax returns that were prepared without professional assistance or by a different tax agent. This review can help identify deductions, offsets or other tax benefits that may have been overlooked. 

Bring in your existing return and our experienced tax agents will assess whether anything was missed. The review is free. If we find deductions or credits you are entitled to and you choose to proceed with the amendment, standard fees apply and those fees are themselves tax deductible in the following year's return.

You do not need to have been an H&R Block client previously. The service is available to anyone who has lodged a return in the past two years, or within the relevant amendment time frame for their situation.
 

What to Bring to Your Second Look Appointment

The more complete your documentation, the more thorough the review. Bring:
 

• Your original Notice of Assessment from the year in question
• A copy of the original tax return if you have it
• Income statements or payment summaries from employers
• Bank statements or interest certificates
• Records of any deductions you think may have been missed: receipts, logbooks, invoices, or records of work-related expenses
• Any investment-related documents: rental property expenses, share dividend statements, managed fund distribution reports
• Your Tax File Number

 
If you are unsure whether a document is relevant, bring it anyway. Our tax experts will work through what applies to your situation.

What Happens After H&R Block Lodges Your Amendment

Once your amendment is prepared and you have approved the changes, we can lodge it electronically on your behalf through the registered agent lodgement system. Once registered, you will receive confirmation from your tax agent. The ATO then processes the amendment and issues a revised Notice of Assessment. If the amendment results in a refund, or a larger refund than your original return, the additional amount is deposited into your nominated bank account. If the amendment results in an amount owing, the Notice of Assessment will set out the payment details and due date.

Processing times vary depending on how the amendment is lodged and its complexity. Paper amendments can take up to 50 business days to process. Online amendments generally process faster and may take around 20 business days or longer, depending on the complexity of the changes and whether the ATO requires additional information.

Will Amending Your Return Get You More Money Back?

In many cases, yes. An amendment is not only a mechanism for fixing errors that cost you - it is also the pathway for claiming entitlements you missed.

Every year, a significant number of Australians who lodged without professional help discover through a Second Look Assessment that their return underrepresented their deductions. The most commonly missed categories are occupation-specific work expenses, vehicle costs for work-related travel, home office deductions, and investment-related costs for property or share investors.

The refund impact of missed deductions depends on your marginal tax rate. For example, a person on a 30% marginal tax rate who missed $3,000 of legitimate deductions could receive up to $900 less than they were entitled to. If those deductions are later claimed through an amendment, the taxpayer may receive an additional refund of up to $900, less any fees associated with the amendment service.

Amendments can also work against you if the original return overstated deductions or understated income. If H&R Block's Second Look Assessment identifies an error that has created a tax advantage you were not entitled to, the correct course is to disclose and correct it. Voluntary disclosure before the ATO identifies the issue is always the better position to be in.

Penalties, Interest, and What the ATO Can Do

The prospect of penalties is what stops many people from acting when they know their return has an error. Understanding how penalties actually work makes the decision to correct much clearer.

When Penalties Apply

Penalties are applied based on the nature of the error, not the act of amending. The broad categories are:
 

• Honest mistakes: where an error was inadvertent and reasonable care was taken. These typically attract no penalty, particularly if corrected promptly through an amendment.
• Careless errors: where a reasonable person would have taken more care. These carry a base penalty of 25% of the tax shortfall.
• Reckless errors: where the risk of incorrect reporting was disregarded. Base penalty of 50% of the tax shortfall.
• Intentional disregard: deliberate misrepresentation. Base penalty of 75% of the tax shortfall.

 
Interest on unpaid tax applies from the original due date of the return where an error resulted in underpaid tax. This runs regardless of whether a penalty applies.

The important point is that penalty amounts are not fixed. The ATO can reduce them based on voluntary disclosure, cooperation, and the taxpayer's prior compliance history. A professionally managed amendment through H&R Block, with a clear explanation of the error and supporting documentation, consistently produces better penalty outcomes than errors the ATO identifies independently.

Why Amending Before the ATO Contacts You Matters

The ATO's data-matching program processes over one billion transactions annually, cross-referencing what individuals report against income data from employers, banks, investment platforms, and sharing economy operators. If your return has an error involving income, there is a real possibility the ATO will identify it.

When the ATO finds an error before the taxpayer has corrected it, the taxpayer loses the voluntary disclosure benefit, and the ATO's view of the error is not shaped by the taxpayer's own explanation. The outcome in terms of penalties and the response required is materially different from a situation where the taxpayer identified and corrected the error first.

The same principle applies to missed deductions. If you suspect your return was not as thorough as it could have been, the Second Look Assessment identifies what was missed while the amendment window is still open.

 

What Happens After You Amend: The Reassessment Process

Once an amendment is lodged, the ATO reviews the changes and issues a revised Notice of Assessment. This document replaces the original assessment for the relevant year and sets out the revised tax liability, refund amount, or amount owing.

If the amendment results in a refund, the ATO deposits the additional amount to your nominated bank account. The timeframe is typically within 20 business days for electronically lodged amendments, though complex amendments or those that require additional review can take longer.
If the amendment results in additional tax owing, the revised Notice of Assessment will state the due date for payment. Interest on the tax shortfall applies from the original due date of the return, not from the date of the amendment.

You can amend a return more than once, provided you remain within the relevant time limit. Each subsequent amendment is assessed on its merits. There is no fixed limit on the number of amendments that can be made to a single year's return, though repeated amendments for the same year may attract closer scrutiny.

In most cases, an amendment does not trigger an audit. The risk of triggering an audit is significantly lower for amendments that are voluntarily lodged, professionally prepared, and accompanied by clear documentation.

Common Mistakes When Amending a Tax Return

• Amending before the original return has been assessed. The original return must be fully processed and a Notice of Assessment issued before an amendment can be lodged. Attempting to amend a return that is still processing causes confusion and does not accelerate the process.
• Amending for a minor arithmetic error the ATO would correct automatically. Small rounding differences are often corrected by the ATO as a matter of course when processing. If the ATO issues an amended assessment correcting a minor error, a separate amendment from the taxpayer is not needed.
• Assuming an amendment can be lodged at any time. The limit applies from the date of the Notice of Assessment, not the current date. Leaving it until the last minute risks missing the window.
• Amending without adequate records. An amendment places the deduction or correction on the record. If the ATO subsequently queries it, you need documentation. Amending without records in hand is not recommended.
• Amending only the obvious error and missing the full picture. An H&R Block Second Look Assessment reviews the entire return, not just the specific item that prompted the amendment. This often surfaces additional entitlements that make the amendment significantly more valuable than fixing the initial error alone.