Stuart Robert, who served as human services and government services minister, fronted the commission on Thursday.

Hundreds of thousands of Australians were sent debt notices under the robodebt scheme that unlawfully recovered more than $750 million using a method of income averaging.

Robert said his department did not provide advice from the Australian Government Solicitor highlighting problems with the way debts were raised when he became minister in May 2019.

The first he heard of it was in a meeting with his department in July of that year.

Robert said after the meeting he “held a strong personal view” that the sole use of averaged income data from the tax office was insufficient to raise a debt.

Yet in media appearances following that meeting, Robert continued to defend the scheme because it was still the government’s policy.

“If I’ve got a personal opinion, my next step is to seek the appropriate advice,” he said.

“Until such time as that arrives, I remain a cabinet minister, and I’m responsible for holding the cabinet line.”

Commissioner Catherine Holmes asked if that included misrepresenting policies to the Australian public.

Robert said he “wouldn’t put it that way” because his personal opinion could be wrong until proven otherwise by the solicitor-general.

“I’ve got to leave room for the fact that I may well be wrong … I can’t just give my personal opinion, I have got to continue to uphold the government policy,” he said.

Former human services department secretary Renee Leon told the commission Robert dismissed legal advice from the solicitor-general in 2019 that the scheme was unlawful.

When she presented the solicitor-general’s findings, Prof Leon said that Robert told her her: “Well, secretary, legal advice is just advice.”

Leon said that when she advised Robert that the department should apologise to customers, admit the error and inform the public of steps to correct it, he replied: “We absolutely will not be doing that. We will double down.”

But Robert rejected this claim and said he presented the solicitor-general advice to the prime minister “within hours”.

Leon told the commission she was forced to end the use of averaging to calculate debts because the government delayed making a decision to do so.

But Robert said it was his department who had “sat on” the legal advice.

“I asked for the advice on the 4th of July, I wanted it, the department took months and months to get it to me and when they had it, they ostensibly sat on it for six weeks to work through what to do,” he said.

-with AAP