Services Australia chasing billions in unpaid debt – including some which may have been unlawfully calculated

Services Australia has had 150 staff working on income-apportionment matters since 30 October. Photograph: Darren England/AAP

Services Australia is chasing billions of dollars in decades-old debt, it has been revealed, some of which may have been incorrectly calculated.

Data released under questions on notice shows that, as at the end of October last year, Services Australia was pursuing $4.9bn in unpaid debts from 829,266 customers. The oldest debt dates back to 1979, with thousands from the 1990s.