The Corrections Department is to lay a formal complaint with TV3 over a journalist who visited Clayton Weatherston in jail.
Weatherston is awaiting sentence after being found guilty last week of murdering former girlfriend Sophie Elliott.
The department said reporter Alison Horwood breached prison security to speak to Weatherston.
It said Horwood did not get chief executive Barry Matthews' approval, which was needed for all media interviews with prisoners.
"No approval was given for a journalist from TV3's 60 Minutes to interview prisoner Clayton Weatherston, nor was any approach made to the department requesting an interview," Mike Martelli, general manager of Mr Matthews' office, told the New Zealand Herald.
TV3 director of news and current affairs Mark Jennings said he understood Ms Horwood had filled out the required form correctly.
An interview that Horwood conducted with Weatherston's parents, Roger and Yuleen, was broadcast on 60 Minutes on Monday.
During the item, Horwood spoke of visiting Weatherston in prison.
