Senior public servants behind the unlawful robodebt scheme will not be investigated by the federal corruption watchdog after it ruled out launching an inquiry.
The National Anti-Corruption Commission said while six public officials were referred for possible investigations into corrupt conduct following a royal commission into robodebt, a fresh examination would not be undertaken.
"The conduct of the six public officials in connection with the robodebt scheme has already been fully explored by the robodebt royal commission and extensively discussed in its final report," a spokesman for the commission said.
"After close consideration of the evidence that was available to the royal commission, the commission has concluded that it is unlikely it would obtain significant new evidence."
The corruption body said it would be undesirable to conduct multiple investigations into the same matter.
Five of the six public servants had already been referred to the Australian Public Service Commission for investigations.
The robodebt scheme ran from 2015 to 2019, using annual tax office data to calculate average fortnightly earnings and automatically issue debt notices to welfare recipients,
Hundreds of thousands of Australians were ensnared by the program, which illegally recovered more than $750 million and was linked to several suicides.
The royal commission's findings were published in July 2023, with an almost 1000-page report recommending individuals be referred for criminal prosecution.
Sections of the report were referred to the corruption watchdog.
"In the absence of a real likelihood of a further investigation producing significant new evidence, it is undesirable for a number of reasons to conduct multiple investigations into the same matter," the corruption watchdog said.
"This includes the risk of inconsistent outcomes, and the oppression involved in subjecting individuals to repeated investigations.
"We understand that our decision not to pursue the referrals from the robodebt royal commission will be difficult for victims, their families and friends."
Another inquiry would not provide any redress to robodebt victims, the commission said.
Greens senator Penny Allman-Payne lashed out at the decision.
"Thousands of people across the country today will be feeling betrayed and angry," she said.
"For many, this will be a deeply triggering and distressing time.
"The commission took nearly a whole year to come to the conclusion that investigations 'would not add value in the public interest'. That's pretty startling."
Coalition spokesman Paul Fletcher said the corruption watchdog was able to come to its own conclusions about robodebt.
"They've explained their reasons, on any view, this matter has been thoroughly examined," he said.
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