We've been hearing from some of the thousands of Australians who have been issued with debt recovery notices by Centrelink in recent weeks.

An automated algorithm is matching data from different government agencies to determine if people have been overpaid—and the onus is on welfare recipients to prove them wrong.

People are being given 21 days—and sometimes less—to supply paperwork from up to five years ago.

Labor MP and Shadow Minister for Human Services, Linda Burney, says the system should be suspended until it's accurate.