TVNZ's former head of Maori programming Shane Taurima failed to adequately disclose his political activities with the Labour Party and was guilty of using the state broadcaster's resources for political purposes, a review has found.
The report, released this afternoon, found no evidence of political bias in TVNZ's programming.
The investigation into allegations of political bias, misuse of resources and conflicts of interests was launched in February after it was revealed that Mr Taurima and three staff members used the TVNZ offices and resources for Labour Party meetings.
The report found that Mr Taurima had not disclosed his "extensive" party political activity during his final year with the company.
It also found that he and three other staff members used TVNZ resources inappropriately for Labour Party political purposes.
None of those staff were still employed by TVNZ.
TVNZ chief executive Kevin Kenrick said in a statement that their activities were "completely unacceptable".
"It's an absolute necessity for our News and Current Affairs service to operate free from political influence.
"We already have a number of checks and balances in place to protect the integrity of news coverage and the review panel has identified additional steps we should take to further strengthen our management of political conflicts of interest.
"We won't be asking our staff to tell us who they vote for. But we think it's reasonable to ask anyone who reports, edits or produces political content to be upfront with us if they're a member of a political party.
"Anyone who creates news content for TVNZ should disclose any political activity beyond passive party membership.
TVNZ board of directors chairman Wayne Walden said the board was pleased there was no evidence to support claims of political bias in TVNZ content.
"While there has clearly been inappropriate use of TVNZ resources to further party political aims, this appears to have been relatively small scale and confined to the activities and aspirations of a single individual and his supporters.
"We welcome the opportunity presented by this report to tighten TVNZ's protocols and raise awareness among existing and future employees of the absolute requirement for our News and Current Affairs division to operate free from political influence,'' he said.
The board had full confidence in the TVNZ executive, Mr Walden said.
He said the broadcaster would immediately take steps to tighten its internal protocols in order to protect its editorial independence.
Mr Taurima acknowledged that it was a mistake to hold a Labour Party meeting at TVNZ and to use TVNZ resources such as email.
"In relation to the cost of these TVNZ resources which the Panel determined were negligible, I have paid back the money concerned."
He said that he had been "vindicated" by the report's findings and was now focused on securing the Labour nomination for Tamaki Makaurau.
"The review has determined what I know to be true - that I have always maintained a professional approach to my work and that I have not and would never allow my political views to affect my editorial or on screen work.
"Irrespective of my political views my job as an interviewer was to apply the same level of scrutiny to all politicians across the political spectrum that I interviewed.
"At no time did I use my position to influence TVNZ coverage to benefit the Labour Party."
Mr Taurima said he had put aside his political ambitions during his time at TVNZ, and had not determined he would stand in Tamaki-Makaurau while he was at the company.
Mr Taurima resigned as head of Maori programmes in February after emails leaked to 3 News showed he was still involved in party meetings despite assuring his bosses he had given up his political aspirations.
He has denied that his affiliation impacted on the editorial content of his work or the programmes he had responsibility for.
He had attempted to become Labour's candidate in the Ikaroa-Rawhiti by-election last year. He stood down from his TVNZ role during the selection process but was given his job back when his bid was unsuccessful.
Labour has repeatedly delayed its selection deadline for Tamaki Makaurau while it waited for the TVNZ report's findings.
Auckland teacher Will Flavell was the only other nomination for the seat, though Maori TV broadcaster Julian Wilcox was also believed to be considering a bid.
If Mr Wilcox was to seek the nomination, Labour would have to waive its requirement for candidates to be a party member for at least 12 months.