Four whistleblowers at the Ministry of Transport suffered "humiliating" reprisals after they raised concerns about convicted fraudster Joanne Harrison, a high-level inquiry has concluded.

And while the staff members were not forced out of their jobs as initially claimed, Harrison's advice meant some of them were made redundant just before Christmas or had requests for a pay rise rejected.

The affected staff members are now in line for compensation, the State Services Commissioner Peter Hughes said at a press conference this afternoon. The size of the payout was confidential.

Hughes said the staff were "salt of the earth" whistleblowers who had suffered at the hands of a woman who "wreaked havoc" within the ministry.

The commission today released the findings of its investigation into allegations by former ministry staff who said they lost their jobs after questioning dubious spending by Harrison, a senior manager at the ministry.

Harrison was sentenced in February to three years and seven months in jail for defrauding the ministry of $750,000.

The investigation by former Deputy State Services Commissioner Sandy Beatie found that four staff members "suffered disadvantage in processes Ms Harrison was involved in".

No staff were made redundant as a direct result of their actions, the report said. The restructure in which they lost their jobs was "legitimate for the ministry to pursue" and was properly signed off.

However, while Harrison did not have direct control over the redundancies, she did provide advice on the process, the report said. This meant the staff members suffered "unnecessary hurt and humiliation".

The staff members were made redundant just before Christmas and seven months before the ministry's planned changes which required the redundancies. Beatie said she could see "no reason" they were stood down when they were.

The staff members then had to train temporary staff members to replace them - an additional cause of humiliation.

"While decisions were properly made by the appropriate ... managers and endorsed by the chief executive, the process followed and particularly the timing of the redundancies was based on advice from Joanne Harrison.

"While there is no definitive evidence that Joanne Harrison engineered the process to exit these staff, the convergence of the events that took place and her involvement in providing advice that gives me concern."

Harrison also directly intervened to prevent a member of the ministry's legal team from getting a pay rise. The staff member had been pursuing concerns raised about her activities.

Hughes said this interference had "every appearance of being punishment" for raising legitimate concerns.

He said the staff members should never have been disadvantaged "because they did the right thing".

"I am making sure these people get redress for what happened to them," he said.

The inquiry found two other ministry staff may have been badly treated by Harrison, but this was not related to whistleblowing and fell outside the terms of the investigation.

Beatie made a series of recommendations, including a requirement that public sector agencies made it easier to raise concerns safely and easily.

She also wants the Government to review the legislation which protected whistleblowers, saying it was now 17 years old and not longer reflected best practice.

The State Services Commission took over the inquiry from the ministry in May, citing the importance of the investigation and the public interest in it.