The taxpayer cost of ad-free TV1

It would cost taxpayers $250 million a year to watch TV1 without any ads, TVNZ's boss has revealed as the Government moves forward with a plan to merge it with RNZ.

Both TVNZ and RNZ bosses fronted up to a Parliamentary select committee on Thursday in the midst of the Government's planned merger - the details of which were announced last week.

"There's a good argument for New Zealand having one strong combined public broadcaster," RNZ chief executive Paul Thompson told journalists following the meeting. 

Kevin Kenrick, chief executive of TVNZ, said: "To me it's a bit like the rebuild of Christchurch, you know? How often do you get an opportunity to design from scratch?"

But TVNZ and RNZ appear to be at odds about whether the merged broadcaster should run ads. RNZ is entirely publicly funded while TVNZ relies on commercials - and they want to keep it that way.

"As a taxpayer, I wouldn't want to see taxpayer money wasted," Kenrick said.

Thompson said: "At its heart... it needs to have public media objectives not commercial objectives."

TVNZ pulled in $300 million in revenue last year with most of it from TV1. Kenrick says to run that channel commercial-free, it would cost taxpayers $250 million a year - and the Government is not ruling anything out.

But Kenrick told media: "Crowding out commercial revenue and replacing that with taxpayer funding doesn't seem like the best way to go about it."

There is also a total difference in culture between the two - and cash-flow. RNZ's boss earns $500,000 a year versus TVNZ's boss who's on $1.5 million.

The tension comes as RNZ announced last week it was planning to remove RNZ Concert from its FM frequency to make way for a youth channel.

But on Wednesday, the chief executive backed down after opposition from ministers - including Prime Minister Jacinda Ardern.

"We expected the feedback to be intense but it was probably more intense and from more quarters than we thought," Thompson told the committee.

The Prime Minister appeared confident about the Government's direction on Thursday, saying: "We reached a good position that RNZ Concert stays on the FM".