The National Anti-Corruption Commission has ruled out an investigation into those referred to it by the robodebt royal commission.

The NACC said on Thursday a corruption investigation into the six unnamed individuals was “unlikely (to) obtain significant new evidence” and “it would not add value in the public interest”.

“The commission is conscious of the impact of the robodebt scheme on individuals and the public, the seniority of the officials involved, and the need to ensure that any corruption issue is fully investigated,” it said.

Findings from the royal commission into robodebt were handed down in July 2023, with an almost 1000-page report recommending individuals be referred for criminal prosecution.

Sections of the report were also referred to the corruption watchdog.

NACC said the conduct of the six public officials involved had already been fully explored by the royal commission and extensively discussed in its final report.

“After close consideration of the evidence that was available to the royal commission, the [NACC] has concluded that it is unlikely it would obtain significant new evidence,” it said.

“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. 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. We encourage anyone experiencing distress to seek support – https://t.co/bb7h1iPmXj

— NACCgovau (@NACCgovau) June 6, 2024

Robodebt was a largely automated – and unlawful – debt recovery program. Kicking off under the former Coalition government in 2015, it falsely accused welfare recipients of owing money to the government and issued debt notices to people identified through a process called income averaging, which compared their reported income with tax office figures.

Hundreds of thousands of Australians were caught up in the debacle, which illegally recovered more than $750 million and was linked to several suicides.

The royal commission heard from former prime ministers Scott Morrison and Malcolm Turnbull and ex-ministers Alan Tudge, Christian Porter and Stuart Robert, as well as public servants. It also heard harrowing stories from more than 100 witnesses.

The scheme was ruled unlawful in 2019 and a settlement of $1.2 billion was reached between robodebt victims and the former government in 2020.

The commission has confirmed that five of the six public officials involved were also the subject of Australian Public Service Commission referrals.

The APSC and the Australian Federal Police are running concurrent inquiries into the scheme.

APS commissioner Gordon de Brouwer told Senate estimates last week that seven findings had so far been made against referred bureaucrats. A further seven continue.

The APSC has also confirmed that four of those facing sanctions were still employed as public servants.

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-with AAP