A convicted fraudster apparently headed an inquiry into workplace harassment just months before she was arrested.
There are now calls for findings from the harassment inquiry at the Department of Conservation (Doc) to be scrapped.
It is the latest development in the case of former Ministry of Transport senior manager Joanne Harrison, who was jailed in February for defrauding the ministry of $750,000.
In a speech on Sunday, New Zealand First leader Winston Peters revealed Harrison was put in charge of an inquiry into harassment within Doc's information systems and management department.
Mr Peters yesterday said Harrison completed a draft report in March 2016, just before her offending came to light.
She was arrested in August on fraud charges.
Mr Peters said her involvement in the inquiry "taints every finding, recommendation, and outcome Doc took''.
"This has a cascade of employment law implications for the staff involved in a report dated March 2016 - only weeks before the truth came out about her crimes.''
A Doc spokeswoman was unable to respond to questions yesterday.
The inquiry's findings and outcomes are not known.
Mr Peters said the latest revelation about Harrison raised further questions about her former boss and ministry chief executive Martin Matthews' judgement.
Mr Matthews led the ministry at the time of the fraud and has since been appointed Auditor-general.
Political parties who approved his appointment said they should have known the full details of his handling of the fraud case when they were considering him for the role.
Labour leader Andrew Little has asked the Speaker to review his appointment, and Mr Peters said he should stand down while a full investigation was carried out.
In a further development yesterday, State Services Commissioner Peter Hughes said he was considering a new investigation into the ministry's handling of the case.
Former ministry staff last week said they were forced out of their jobs after raising concerns about Harrison's behaviour.
As a result, newly appointed Secretary of Transport Peter Mersi set up an independent process to look into their concerns.
Mr Hughes said he had received an email from former staff members raising concerns with this process.
"I am treating this as a request for SSC to investigate the concerns they have raised.''
He said public servants who had concerns about an issue needed to raise them so they could be properly considered and addressed.
Radio New Zealand reported two former staff members at the ministry believed they were targeted in a ministry restructuring after they pointed out fake invoices and dubious travel.
Prime Minister Bill English yesterday said the State Services Commissioner and the Department of Prime Minister and Cabinet had investigated the ministry's handling of the case and had not found any wrongdoing. However, "if there was any new information, such as from these whistleblowers, they have to take that into account''.
