1. Failure to Declare All Income
Not reporting all income sources—such as wages, investment earnings, side hustles, cryptocurrency gains, or government payments—remains one of the most frequent and costly errors.
2. Inaccurate Work-Related Deductions
Many taxpayers incorrectly claim work-related expenses, such as vehicles, phones, or uniforms, without adequate records or by including private use components.
3. Outdated Personal Details
Incorrect addresses, names, or bank account details can delay refunds and may trigger unnecessary compliance checks.
4. Claiming Deductions Without Evidence
Deductions must be supported by valid records such as receipts, invoices, or logbooks. Without documentation, claims may be denied if reviewed by the ATO.
5. Private Health Insurance and Medicare Errors
Misreporting private health insurance details or failing to account for the Medicare levy surcharge often results in calculation errors and unexpected liabilities.
6. Omitting Capital Gains on Property or Shares
Failing to declare the sale of investment properties, shares, or cryptocurrency is a major red flag, as the ATO uses sophisticated data-matching to track disposals.
7. Not Reporting Overseas Income
Foreign employment income, investments, or rental earnings must be disclosed, even if tax has already been paid overseas. Non-disclosure is a common compliance issue.
8. Misclassifying Investment Property Expenses
Repairs and maintenance are immediately deductible, while improvements must be capitalised or depreciated. Confusing the two categories is a frequent error among property investors.
9. Incorrect Spouse or Dependent Information
Providing inaccurate details about a spouse’s income or dependent status can distort offsets, family tax benefits, and Medicare levy calculations.
10. DIY Lodging Without Professional Advice
While DIY tax software may appear convenient, it often results in overlooked deductions and costly mistakes. Engaging a registered tax agent ensures accuracy, compliance, and peace of mind.
