The federal government is under pressure to detail a breakdown of funds returned to Australians served with unlawful debts.
The "robodebt" scheme matching Australian Taxation Office and Centrelink data to claw back welfare benefits the government claimed were overpaid was deemed unlawful by the Federal Court.
Labor and Greens senators want Services Australia to release publicly the total value of debts across class action members and the average share of the cumulative $1.2 billion settlement sum once finalised.
The latest report of an inquiry looking at the saga lashed the government for not releasing information about legal advice regarding the scheme's operation on the grounds of public interest immunity.
"Despite numerous attempts to obtain the information, the committee has been prevented from thoroughly assessing whether the government knew of the insufficient legal basis of the program due to repeated and poorly articulated public interest immunity claims," the fifth interim report said.
It requested Government Services Minister Linda Reynolds table in parliament by 1pm on Wednesday requested documents or explain her failure to do so.
Government senators Wendy Askew and Hollie Hughes said the documents were exempt under freedom of information laws and public interest immunity claims should be respected.
They said 98 per cent of refunds had been made, with around 426,400 people getting money back or having their debts wiped.
