Senior Human Services figures "effectively co-wrote" an independent Commonwealth Ombudsman report into their own department's dodgy robodebt scheme.
That was revealed when the royal commission into the scheme that falsely accused welfare recipients of owing money continued on Monday, with former senior Department of Human Services - now Services Australia - official Jason McNamara giving evidence.
Mr McNamara readily admitted he was trying to influence the Ombudsman when they wrote to the department in 2017 seeking feedback for a report it was writing into their shift to an automated debt recovery system.
One department official told colleagues via email it was "a great opportunity to effectively co-write the report".
That email suggested the Ombudsman could copy and paste their content into the final report.
The report did identify a number of flaws in the scheme but stopped short of declaring its 'income averaging' debt calculation process unlawful.
Mr McNamara was then shown a number of edits made to the language in the draft report that looked to downplay the negative impact of the scheme.
Asked by counsel assisting the commission Angus Scott if one particular edit was to produce a sentence less scathing of the program, Mr McNamara responded: "Yes, definitely".
They also had input to the recommendations the Ombudsman report made.
Mr McNamara did not accept department influence challenged the Ombudsman's neutrality, saying the practice was "quite normal" and they were free to reject the suggestions if they wanted.
The commission was shown Mr McNamara applied for the position of Treasury's deputy secretary and boasted he had "shaped" the Ombudsman's report.
It also saw evidence former Human Services Minister Alan Tudge pointed to the Ombudsman report in face of criticism of the scheme through a Senate report.
Robodebt, initiated under the former Liberal-National government, issued automated debt notices via a process called income averaging, which compared people's reported income with tax office figures.
Averaging recipients' income meant welfare payments they were entitled to in certain weeks were later ruled as debt.
Mr McNamara would not accept commissioner Catherine Holmes' assertion the unlawful income averaging was "a guess", insisting it should be described as "an estimate".
The commission is investigating how the scheme, which operated between 2015 and 2020, went ahead despite government departments knowing the debt calculation method was unlawful.
Earlier, senior counsel assisting the commission Justin Greggery KC said relevant former Morrison government ministers including Mr Tudge, Stuart Robert, Christian Porter, Dan Tehan and Paul Fletcher are likely to be called to give evidence.
The social services and human services ministers at the time the scheme was established - Scott Morrison and Marise Payne respectively - are already scheduled to front hearings next week.
Mr Gregg said the other ministers would be called in a subsequent hearing block. The next block of public hearings are set for January 23 to February 3.
Ms Payne will give evidence next Tuesday before Mr Morrison takes the stand on Wednesday.
