A fresh investigation is being launched into Centrelink's controversial "robo-debt" recovery program, following claims from a whistleblower of serious failures.
The welfare agency has been under fire over its automated debt recovery scheme for more than 18 months, after scores of people were incorrectly targeted in a data-matching blitz on supposed over-payments.
Debt recovery notices were sent to 20,000 welfare recipients who were later found to owe less money or even nothing.
Independent federal MP Andrew Wilkie has secured agreement from the commonwealth ombudsman to launch another investigation into the robo-debt program.
Mr Wilkie is concerned people who provide pay slips rather than bank statements may be incurring higher debts, believing the system does not factor in gross versus net income.
He is also worried people are receiving double or triple debts because one employer has been recorded under several different names.
Mr Wilkie restated his calls for the "deeply flawed" program to be shut down and replaced.
"The fact is that the robo-debt system should have been shut down a long time ago," he said on Wednesday.
"But instead the government has continued to let it loose on everyday Australians, saddling them with nonsensical and often incorrect debts, sometimes in the tens of thousands of dollars."
The Department of Human Services insists there are safeguards in place to ensure people who provide pay slips instead of bank statements are not disadvantaged.
It has also highlighted there are checks in place to avoid discrepancies with employer names, with users able to select an employer's ABN if the name is unfamiliar.
"In relation to a complaint from Mr Wilkie, the ombudsman has sought information from the department about the online compliance system and debt recovery," Human Services spokesman Hank Jongen said.
"This is not a review of the system itself and is in relation to a specific complaint."
Mr Jongen pointed out the commonwealth ombudsman last year found it was "entirely reasonable and appropriate" for the department to ask welfare recipients to explain data-matching discrepancies.
The ombudsman also found debts raised through the controversial program were consistent with earlier manual investigations.
Mr Wilkie said nobody disagreed with asking Centrelink clients who had been genuinely overpaid to hand the money back.
"You do need a system but it's got to work. This system doesn't work and it can't be made to work," he said.