Key bureaucrats singled out in robodebt report

* Kathryn Campbell, former secretary of human services and social services departments

Ms Campbell was involved in a new policy proposal to federal cabinet which "was likely to mislead because it contained no reference to income averaging or the need for legislative change", the report said.

She described this as an "oversight", but the commission found that would have been extraordinary for someone of her seniority and experience.

It said the weight of the evidence instead led to the conclusion that Ms Campbell knew of the misleading effect of the policy proposal but chose to stay silent knowing that then-minister Scott Morrison wanted to pursue the plan and the government wouldn't achieve its desired savings without income-averaging.

* Serena Wilson, former social services department deputy secretary

Ms Wilson told the inquiry she was only made aware in January 2017 that income averaging was part of the scheme, but the report said the commission did not accept she was unaware the system was being used before that date.

* Annette Musolino, former human services department chief counsel and senior executive

The commission found Ms Musolino was made aware in a March 2017 email that "in 2014 DSS had obtained internal legal advice to the effect that income averaging was unlawful".

The email "could only have reinforced in Ms Musolino's mind what she had already learned ... that the legal arguments in support of income averaging were weak and unconvincing and involved substantial legal risk", the report said.

Despite this, Ms Musolino took no steps to provide legal advice to departmental executives about the extent of that risk and the need to obtain independent, external advice.

"She did not do so because she knew that such advice was unwanted by them," the report said.

* Renee Leon, former human services secretary.

The commission found some of her actions in regard to the Masterton litigation - the key test case which exposed problems with robodebt - were "designed to avoid public and political scrutiny of the scheme".

Australian Associated Press