What triggers an ATO audit in Australia — what draws attention to your return?

The ATO uses sophisticated data analytics and third-party data matching to identify returns that appear inconsistent or suspicious. While anyone can be audited, certain patterns significantly raise the risk.

Common ATO audit triggers:

• Deductions out of proportion to income: Claiming deductions that are very high relative to your income — particularly work-related expenses — flags a return for review. The ATO publishes benchmark data by occupation.
• Large or unusual deductions without supporting records: Especially car expense claims, home office claims, or rental property deductions that exceed typical amounts for your industry.
• Cryptocurrency activity: The ATO receives data from Australian crypto exchanges and actively cross-references declared income against exchange data. Not declaring crypto gains is one of the highest-risk areas.
• Rental income/deductions: The ATO specifically reviews rental property returns for overclaiming of interest, repairs vs. capital improvements, and depreciation.
• Cash economy businesses: Businesses dealing in cash (trades, hospitality, retail) are under ongoing scrutiny through ATO taskforces.
• Data matching: The ATO matches data from banks, share registries, state revenue offices, Centrelink, and employers. Inconsistencies between this data and your return can trigger a review.
• Significant income changes year-over-year: A sudden drop in reported income when your lifestyle indicators haven't changed can attract scrutiny.

What to do: Maintain good records for at least 5 years, claim only what you are legally entitled to, and declare all income including cash, crypto, and foreign income. If you receive an audit letter, engage a registered tax agent immediately.