A former Coalition minister has told the Robodebt royal commission she does not know when the need for policy and law changes for the scheme "dropped off the radar".
Marise Payne has given evidence to public hearings in Brisbane, which are examining the unlawful scheme.
She was the minister for human services from 2013, when the former government first took office, until September 2015.
The commission has previously heard how the idea originated in the Department of Human Services (DHS) and was developed between it and the Department of Social Services (DSS).
It has also previously heard evidence that a February 2015 executive minute to Scott Morrison, who was then minister for social services, said "policy and legislative change" would be needed, but the budget submission from DSS did not contain that phrase.
"How did the identification of the problem in the lead up to the final executive minute drop off the radar by the time, it seems, the (Expenditure) Review Committee considered the proposal?" Senior Counsel Assisting Justin Greggery asked.
"Mr Greggery, I don't know the answer to that question and I say that in all transparency," Ms Payne responded.
"There is an expectation however that when agencies advise you on the face of a brief that they are working together to address these issues … that the officials are doing that," she said.
Earlier, Commissioner Catherine Holmes asked if it would be extraordinary for Ms Payne not to review an official new policy proposal, which would be implemented by her department, before it went to Cabinet's Expenditure Review Committee.
"I would say commissioner, given the volume of material that was involved in the budget process, that there would be potentially a number of items that I would not necessarily see as a junior minister," she said.
"I have endeavoured to assist the commission, I cannot find a record of a specific review of the NPP.
"My recollection now, from 2022, to what I did in 2015 does not let me tell you the answer to that question, I'm sorry."
Ms Payne told the commission that in 2015 there were more than 30 new policy proposals under the senior minister, Scott Morrison's name, and not every one would have come across her desk.
As junior minister, she only attended Cabinet and ERC meetings when invited.
Mr Greggery also asked Senator Payne about the estimate that the measure would save the budget more than $1 billion.
"Can you now say, that as a significant savings measure, it had a degree of attractiveness to a government that worked with a view towards a balanced budget?"
"I can't say that," Ms Payne responded.
"The approach that I understood to be a priority was to ensure that we were paying the right people the right amounts of support … avoiding paying the wrong people, avoiding fraud and ensuring that where payments were made in the wrong context or where fraud occurred that we could recoup those savings."
Ms Payne has denied a large crossbench was putting the Coalition government off including proposals in the 2015-16 budget that would require legislation.
Payne asked about media releases spruiking Robodebt
The royal commission was shown two ministerial media releases that mentioned the new compliance measures — one discussed three separate cases of fraud, including thefts of $50,000 and $95,000 — and the second highlighted a case where someone had defrauded $200,000.
Commissioner Holmes questioned Ms Payne about why the releases did not distinguish between criminal activity and people who would be targeted by the Robodebt scheme.
She responded that press releases enable a short, sharp message and journalists can ask for further information if they want.
While speaking about the specific case of the $200,000 fraud, Ms Payne said: "It's not the case, commissioner, that this is isolated unfortunately."
"No, but it doesn't bear much resemblance to the sort of person on Youth Allowance, who hadn't worked for an entire year but found their income being averaged … and got told they had a debt, who was the subject of this budget measure and is really being talked about in the same context," Commissioner Holmes said.
"I'm not suggesting at all that they are in the same category," Ms Payne responded.
"One view of this kind of use of media is that it was really designed to give the impression that the people subject to the budget measure deserved no sympathy at all because they were really criminals," Commissioner Holmes said.
"Commissioner that was not my intention, not my thinking, not my approach," Senator Payne said.
"But in relation to fraud, and I think these are three strong examples, I would be very clear that it can't be tolerated by government."
