Attorney-General Christian Porter has refused to detail legal advice the Morrison government received before changing a fundamental plank of its controversial robodebt program.
A fortnight out from a critical Federal Court challenge of the debt recovery program, The Canberra Times revealed the Department of Human Services would no longer raise debts, when averaged income data from the tax office is the only evidence of the overpayment.
"You could imagine that any government, depending on where those matters are in the process of litigation, seeks advice on those individual matters, and that's fed in, obviously, to decision-making in the Department of Human Services and in the minister's office," Mr Porter told the National Press Club on Wednesday.
However Mr Porter would not say what that advice was.
"Will I waive privilege or government legal advice? You'd expect the answer's no. But there are matters that have been conducted through the courts, two individual matters, and as you noted, there is a class action on foot," Mr Porter said.
The legality of using averaged data to raise debts is due to be tested in the Federal Court on December 2, through a case being run by Victoria Legal Aid.
Gordon Legal, which has been mounting a separate class action against the debt recovery program, has also revealed it wrote to Centrelink last Friday warning it the suit was about to commence.
While the firm has not received a response to that letter, the internal Department of Human Services email announcing the changes was sent the following Monday.
Gordon Legal said it will continue with class action regardless, as it was unclear whether Centrelink would return money taken from its clients.
More than 4000 people have joined the class action so far.
It was also yet to be seen whether Centrelink would compensate people affected by robodebt or withdraw the many thousands of debt notices still outstanding.
Documents were served on the Commonwealth on Wednesday.
"In our view, the changes announced by Centrelink yesterday contain a number of important concessions," the firm said.
"It now appears that Centrelink acknowledges, at least in some way, that averages calculated from annual ATO data are not a substitute for calculating actual fortnightly earnings; and the onus should be on Centrelink to establish that a debt is owed, rather than recipients of welfare payments being required to prove that they were entitled to receive the benefits paid to them."
Gordon Legal's senior partner Peter Gordon said the concession by the government proved the scheme was illegal.
"I think the announcement yesterday by the government was only consistent with the penny dropping inside the echelons of the government that this scheme is illegal," Mr Gordon said.
"They understand they're about to have to defend it in court, they've gone to the lawyers and we assume they've had the same advice from the lawyers as every other lawyer I've referred to today
"If that's wrong, let them say so. Let them come out and say they're in a position to defend this and we will seek an urgent hearing before the court to test that proposition."
Meanwhile Government Services Minister Stuart Robert has refused to answer key questions about the decision.
While Mr Robert downplayed the changes as a "refinement of the system", the internal staff email revealed the onus would no longer be on welfare recipients to prove they do not owe Centrelink money - a major change to the program.
There will also be a review of hundreds of thousands of debts raised, where tax office data was the only proof a debt existed.
Mr Robert's office refused to say how many people were affected by the decision, or whether debts beyond the seven-year retention period would be wiped.
His office also refused to comment on how the reviews would be staffed, and whether Services Australia staff would obtain records direct from employers.
Instead, they sent a statement from the Department of Human Services, which said, "DHS are currently in the process of identifying the small cohort of people the refinement applies to, however, the group is limited to those who did not respond at all to requests for the clarification of discrepancies."
Labor's government services spokesman Bill Shorten accused the government of "arrogantly" refusing to admit to any flaws with the program.
"Minister Stuart Robert's pausing of the scheme and junking of its key features this week is a very late admission there is something rotten at the core of robodebt," Mr Shorten said.