Spokeswoman Megan Richards said that the ad reflected a new approach to advertising, but insisted it did not reflect a change in the approach. The proximity of the Cadbury advertorial to genuine current affairs shows was not an issue, she said.
"There is nothing new - it's drawing a long bow to say we should not have interviews in ads - advertising is changing," Richards said.
Chapman has been presenter for Back Benches for several years, but TVNZ scrapped the show when it lost funding for the public service channel TVNZ 7. However, TVNZ received $629,000 of taxpayer funding to make the show for Prime, with Chapman in an interviewing role.
The Cadbury ad this week was part of an ad campaign marketed as "The Extra Mile'' which was made by Black Sand, a joint venture between TVNZ and the private company
Brandworld.
TVNZ has admitted it slipped up putting an advertorial commercial onto its news website, but says it is looking for ways to get "paid content" included on its news wesbite.
The "Extra Mile" material was distinct from editorial and advertising and blurred the lines.
But Richards acknowledged that at heart the Cadbury advertorial was still an ad.
Journalists are traditionally barred from making commercials because it reflects on their independence, but Chapman has no issues. "I'm not a journalist and I have never said I am one," he said. The Cadbury ad was about Fair Trade and he had always supported Fair Trade.
"I'm a broadcaster with a background in advertising, and I've been involved in advertising for a long time," he said.