TVNZ has apologised to viewers after featuring a hoax interview with a man purporting to be a pro-commercial whaling supporter.
"Jay Pryor" was interviewed by Paul Henry on Breakfast this morning and went on to be photographed with Prime Minister John Key, following the interview.
A TVNZ publicist said the man had gone to reasonable lengths to dupe the public by creating a false name and setting up a fake website.
But TVNZ believes the interviewee is a television comedian named Guy Williams.
"As a result of this prank, Breakfast is reviewing its set-up interview procedures and apologises to viewers for the error," TVNZ said in a statement.
The statement said Mr Henry's suspicions were raised during the on-air interview because of the interviewee's lack of knowledge, despite a Breakfast producer having spoken to "Jay Pryor" the night before the interview and believing he was plausible.
"We do not know whether the person spoken to by the producer the previous night was the same person who appeared on Breakfast," TVNZ said.
"Mr Pryor" was also quoted in a pro-whaling article in the Sunday News.
Sunday News deputy editor Lee Umbers was unaware of the prank but said they would look into the incident.
"Obviously if it is a sham then I'm unhappy and we will invesigate how it made it through our processes."
While the interviewee was at TVNZ he had his photograph taken with Prime Minister, John Key who was also on Breakfast this morning.
Breakfast producers have advised Mr Key's office of the event.
TV1 said it was reviewing its editorial policy regarding interviews following the hoax.
It has also removed the clip from YouTube.