Around one in ten Australians claim the maximum in tax deductions allowed without needing receipts, according to new analysis of ATO tax data.

But one of the country’s leading income tax experts has argued it still might be taxpayers who are getting rorted.

More than one million of the country’s 12 million taxpayers make claims at this threshold, meaning Australians have potentially claimed hundreds of millions of dollars in expenses without receipts.

Dr Adrian Raftery from Deakin University said the claimants fell into two groups.

"One of them is made up of those that don’t have any deductions at all, knowing that they won’t have any fear about the ATO in terms of audited investigation,” he said.

"Then there’s the other type who are too lazy, who don’t know everything they’re legitimately entitled to and who are really losing out."

He noted that while some might be claiming more than they are entitled, more taxpayers will under-claim.

And he said that the failure for the $300 threshold to increase over time in line with the cost of living means that the government has probably benefited most from the no-receipt threshold in the end.

"The $300 figure has been around since Adam was a boy but it hasn’t been adjusted for CPI,” he said.

"Most government regulations are adjusted for CPI, but work-related deductions is one area that hasn’t been."

The ATO releases the figures from two per cent of all Australians’ tax returns each year in a “sample file”.

According to the most recent file from 2013-14, at least 25,000 returns claimed around the $300 mark from a pool of 259,000. Applying the proportion across the country’s 12 million taxpayers establishes more than a million returns at the receipt-free threshold.

The ATO's guidance for people preparing their returns states "if your total claim for all work-related expenses exceeds $300, you must have written evidence".

More than one third of returns claimed zero deductions.

Agents vs DIY

The data also shows that agent-prepared tax returns claim nearly $550 more on average in deductions than those that are self-prepared. The pattern persists across each income band.

Ian Taylor, Chair of the Tax Practitioners Board said tax agents are more aware of the deductions that can be legitimately claimed.

"That's what you'd expect, that an agent with the experience, knowledge and education, would know more about what is able to be claimed than a person off the street with no tax knowledge."

Dr Raftery agreed, though noted Australians using tax agents probably have more complicated returns.

"If you have a really simple return, an agent won’t miraculously find an extra thousand dollars."

The Tax Practitioners Board advises Australians to make sure their agent is on the National Register.

Original article published on SBS.com.au on 31 October 2016