In the 2017-18 financial year, more than 2.2 million Australians claimed over $47 billon in deductions and the Australian Taxation Office (ATO) thinks that is too much - one in ten is estimated to contain errors.

4,500 audits of rental property deductions will be undertaken this year with the focus on over-claimed interest, capital works claimed as repairs, incorrect apportionment of expenses for holiday homes let out to others, and omitted income from accommodation sharing. Deliberate cases of over-claiming are treated harshly with penalties of up to 75% of the claim.  In one case exposed by the ATO, a taxpayer had to pay back $12,000 in claims for deductions against a holiday home that was not genuinely available for rent and was blocked out during the holiday season. In another, a taxpayer paid back $5,500 because they had not apportioned their rental interest deduction to account for redraws on their investment loan to pay for living expenses.