A National Anti-Corruption Commission inquiry on Wednesday found two of six people referred to it for investigation engaged in corrupt conduct but ruled out referring them to face criminal charges.
The remaining four were cleared of corruption, including former prime minister Scott Morrison, who initiated the scheme while social services minister.
The outcome came as no surprise to Melbourne mother Felicity de Somerville, who had $11,500 drained by Centrelink from her bank account without warning under the scheme in 2017.
"Grossly disappointing but not surprising," she said when asked by AAP what she made of the decision not to push for criminal charges.
"I don't think any Australian should be surprised they're not going to take accountability for this and that no one's going to get in trouble, because that's the culture we're breeding."
The former nurse had just finished maternity leave when she found her account had been debited the equivalent of six months wages overnight despite having agreed to a payment plan.
It left her unable to afford medical care for her daughter, who was unwell at the time and caused immense distress for her and her husband, a welder then earning $45,000 a year.
"It really was horrible but I count myself lucky compared to what some others went through," Ms de Somerville said.
The watchdog found ex-departmental general manager of business integrity Mark Withnell carried out corrupt conduct by intentionally misleading the Department of Social Services during the preparation of a cabinet submission in 2015.
It also found department deputy secretary Serena Wilson carried out corrupt conduct by misleading the Commonwealth Ombudsman during an investigation in 2017.
But the watchdog said the findings would not be referred to the Commonwealth Department of Public Prosecutions to consider criminal charges.
"There was insufficient admissible evidence to establish the alleged offences against either Mr Withnell or Ms Wilson beyond reasonable doubt," the report said.
"Key admissions and statements made during this investigation are not admissible in criminal proceedings."
Mr Morrison was found not to be corrupt.
His failure to realise that bureaucratic advice was misleading was put down to shortcomings by federal departments.
He welcomed the findings in a lengthy statement on Wednesday, sympathising with those affected by the scheme and insisting department officials were to blame.
"The NACC has rightly concluded that ministers must be able to rely on the accuracy of the advice provided by their departments, especially on matters of technical expertise, and receive that advice in good faith," he said.
"Whether they follow that advice is a matter for those ministers. In this case, I relied upon, and followed, that advice.
"The departmental advice and warranties provided to ministers were wrong."
The corruption watchdog did not make recommendations in its final report, which followed referrals from the royal commission into the robodebt scheme.
Between 2016 and 2019, the former coalition government's robodebt scheme recovered more than $750 million from almost 400,000 people.
Many welfare recipients were falsely accused of owing the government money and the program was linked to several suicides.
The Albanese government has promised it will release a sealed section of the robodebt royal commission's final report when the investigation ends.
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