Data from online trading site eBay has helped Australian social welfare officials catch out dozens of means-tested beneficiaries who are not declaring big profits from internet sales.
The welfare bureaucracy, Centrelink, compared its payment records with the activity of 15,000 people who are running profitable businesses.
It identified 25 people who must repay more than $A800,000 in payments to which they were not entitled, the ABC reports.
Minister for Human Services Kim Carr says about 100 cases warranted further investigation.
"About 25 debts have already been raised, with the average debt amount about $A32,000 - roughly double the average debt for other types of investigations over the past two financial years," he says.
Centrelink general manager Hank Jongen says some matters had been referred to the director of public prosecutions.
"We are not looking at people who are selling their grandma's vase or an old record collection. We are not chasing hobby users," he says.
"What we're doing is identifying people who have deliberately hidden their income in excess of $20,000 a year."
Senator Carr says the Government will continue the online checks as it cracks down on people who are not honest about their circumstances and deliberately defraud the Government.