TVNZ's Pacific correspondent Barbara Dreaver has been released after spending four hours detained by authorities in Nauru.
Ms Dreaver was detained at around 1pm (local time) after interviewing a refugee, World Vision told TVNZ.
Ms Dreaver was in Nauru reporting on the Pacific Islands Forum. Her media accreditation for the conference has been revoked, TVNZ reports.
Foreign Minister Winston Peters told media the incident was being taken "seriously."
When asked whether he was concerned about press freedom in Nauru, Mr Peters told journalists "You're here. You look pretty free to me."
"I don't know whether there's some offence that's been committed or not committed but we are trying to find out. We are trying to find out both sides of the story."
National's spokesperson for foreign affairs Todd McClay says the detention is unacceptable.
"Mr Peters must seek assurances from the Nauru Government that other members of the media will not be under threat of detention or interference," Mr McClay said.
Prime Minister Jacinda Ardern says she's pleased Ms Dreaver has been released.
"This Government believes in freedom of the press, throughout the world, and of course that includes the entire Pacific region," Ms Ardern said.
The Nauru government announced in July it would be barring the Australian Broadcasting Corporation (ABC) from attending the Pacific Island Forum. The move was condemned by media, including New Zealand's Parliamentary Press Gallery.