The former head of the independent watchdog which investigated the agencies responsible for the robodebt program will be questioned by the royal commission.

Michael Manthorpe served as Commonwealth Ombudsman between 2017 and 2021 and will front the commission on Wednesday.

The commission is seeking to understand the role of the Ombudsman, whose initial report identified a number of flaws in the scheme but stopped short of declaring its “income averaging” debt calculation process unlawful.

This report, conducted before Mr Manthorpe took on the role, was used by the former coalition government to defend the scheme continuing.

The robodebt scheme ran from 2015 to 2019 and used income averaging of tax office data to calculate and raise debts.

The commission is examining how the scheme was allowed to continue, given significant concerns about its legality raised by early 2017.

The commission previously heard senior human services officers “effectively co-wrote” the Ombudsman report into their own department’s dodgy scheme.

Senior public servant Jason McNamara readily admitted he was trying to influence the Ombudsman when they wrote to the department seeking feedback for the report about their shift to an automated debt recovery system.

More than $750 million from 380,000 people was unlawfully recovered through the program and the automated debt notices have been blamed for contributing to multiple suicides.

Meanwhile, Deloitte partner Elea Wurth – tasked by the commission with producing a technical study of robodebt – said a review found artificial intelligence was not present in the program.

Rather it was a “relatively basic” automation system that could not learn from mistakes or become more accurate over time, unlike other AI programs that have the ability to “self-learn”.

“The robodebt scheme did not have algorithms that allowed for any self-learning over time – it was very defined and specific to achieve a very specific goal,” Dr Wurth said.

“It was extremely rigid. Once those rules have been coded, the system itself stayed in place until a human comes in and changes the rules.”

Dr Wurth said the Deloitte review also did not find any risk management frameworks within the department of human services related to the program.

She said while there were policies in place regarding interactions between the two agencies running robodebt, there was not specific governance procedures for the program itself.

The Deloitte report recommended methods to improve trust with automated programs in future, including “human-centred design”.

“When you have a system that is interacting with Australians, especially those that are vulnerable, systems must be designed with the human at the centre,” Dr Wurth said.

– AAP