An accountant has urged Aussies to declare every penny they earn after the ATO uncovered a man's $100,000 side hustle selling used car parts. 

Tax Invest Accounting director Belinda Raso said the ATO's data matching program was cracking down on those who didn't declare income outside of their full-time job.

Earnings from eBay, PayPal, Amazon and Square are now reported to the ATO, with a growing number of secret side hustlers getting a shock at tax time. 

'Most people don't realise that these transactions actually get reported to the ATO on an annual basis,' Ms Raso said in a TikTok video. 

'Since the first of July, 2023, this data matching program has actually been extended.'

Ms Raso gave the example of a client who 'swore black and blue' that he didn't have any other income outside of his full-time job. 

'When he presented for his 2024 tax return he was shocked to find that Square Merchant Facility had actually reported nearly $100,000 in income received by him in that financial year,' she said. 

The client eventually confessed he had been using Square to buy spare parts through Facebook Marketplace and sell them on for a profit. 

Accountant Belinda Raso (pictured) explained how the ATO is using data matching to expose Aussies not reporting earnings from their side hustles

Accountant Belinda Raso (pictured) explained how the ATO is using data matching to expose Aussies not reporting earnings from their side hustles

Earnings from eBay, PayPal, Amazon and Square are now reported to the ATO, with a growing number of side hustlers getting a huge shock at tax time (stock)

Earnings from eBay, PayPal, Amazon and Square are now reported to the ATO, with a growing number of side hustlers getting a huge shock at tax time (stock)

He was ultimately liable for income tax and GST, as his earnings exceeded $75,000. 

The ATO's data-matching program is targeting Aussies earning more than $12,000 on platforms like Amazon and eBay. 

Ms Raso said the days of having secret side hustles are over. 

She urged every Australian with a side hustle to check what information is being reported in their name on their myGov account.

You can do this by logging into your account and click on 'Tax', 'Manage' and then 'Reported Transactions'.

Ms Raso said those who had already lodged their tax returns and received a refund weren't automatically in the clear. 

This is because the ATO can go back two years or more if they suspect there has been tax evasion.

Almost 3.2million Australians had taken on side hustles or plan to in the next 12 months to tackle rising living costs, according to the new Deel Australian Payday Expectations Report.