Twelve current and former public servants failed to show care, integrity and due diligence when they designed and delivered an unlawful welfare debt recovery scheme.
The officials breached their code of conduct 97 times through their involvement with the robodebt program, the Australian Public Service Commission found.
"In their dogged pursuit to deliver on a government priority, some respondents lost their way," a task force report released on Friday said.
"These public servants lost their objectivity and, in all likelihood, drowned out the deafening and growing criticisms of the scheme to pursue an operational objective."
Four people still working in the public service have been slapped with sanctions ranging from fines, demotions, reprimands and one had their salary reduced.
But there is no framework for punishing a former employee and it is unclear how the others who have retired or resigned would be treated.
Many claimed they had behaved ethically because they acted in line with rules, but the report said they should have considered whether the robodebt program was a "sound and fair" public policy.
"This narrow understanding of the 'ethical' value meant that little regard was paid to whether decisions were, in fact, ethical," the commission's report read.
For example, the scheme automatically calculated debt by averaging an individual's income, but this often failed to accurately reflect their earnings and many were ordered to pay more than they owed.Â
The commission found "little evidence" of any concern or assessment about whether this approach was the right thing to do, particularly when dealing with vulnerable people who may not have the records necessary to disprove their debt notices.
The report found the workplace culture did not foster critical discussion over the robodebt scheme and any criticism was often perceived as delaying progress towards implementing government policy.
This was because the intimidating senior leadership created a culture where employees felt they could not raise risks and issues.
Some higher-ups would also deflect accountability when they had delegated large and unsustainable amounts of work to junior staff.
This would later be used as a justification to explain why the department had not paid enough attention to robodebt's legal, ethical and operation risks.
No single person was accountable for the scheme, the report said, but the chain reaction of multiple individual failures led to progressive systemic problems.
Between 2015 and 2019, the botched robodebt scheme set up by the coalition government automatically used tax office data to calculate average earnings and issue debt notices.
Robodebt recovered more than $750 million from almost 400,000 people.
Many welfare recipients were falsely accused of owing the government money and the scheme was linked to several suicides.
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