TVNZ's chief executive Kevin Kenrick says in hindsight it was a mistake to take Shane Taurima back on after Taurima's first attempt to enter politics for Labour, but said Mr Taurima had assured them he had no further political ambitions.
Mr Taurima resigned yesterday after confirming to his bosses that he hoped to seek Labour's candidacy for the Tamaki Makaurau electorate.
Leaked documents given to 3 News showed he had taken part in a Labour Party Tamaki Makaurau electorate meeting on how to win the Maori vote and that TVNZ staff had hosted a Labour Party meeting in TVNZ's offices last August, although Mr Taurima has denied knowing about the meeting.
In a statement, Mr Kenrick announced TVNZ would call in an external expert to investigate the work of the Maori and Pacific unit Mr Taurima led over the last year to ensure its editorial independence had not been impacted on.
It will also investigate the use by some staff of TVNZ resources, such as its offices and email system, for party political activities.