"This isn't something that's just happened, this is a long-term trend over the last year and a half."
He said when Seven Sharp launched in 2013 TVNZ "gifted MediaWorks a massive opportunity". But since a revamp of the show with Mike Hosking, Campbell Live hasn't been able to beat it.
"It's not that it's not important, or not relevant, it's just that people don't watch it," Mr Cunliffe said.
Ratings for Campbell's show last night were the highest in the week for the show after he issued a plea for people to watch.
Campbell Live drew an audience of 241,870 last night, compared with 233,120 on Wednesday night and 213,450 on Tuesday night, according to Throng.
Twitter outrage
An uproar on social media and an online petition to save the show was useless unless people tuned in, Mr Cunliffe said.
"There's only one way to save Campbell Live, and only one petition you need to be involved in, and that's watching it."
This is a commercial decision... the reality is unless MediaWorks can sell advertising around it, it's pointless."
Mr Cunliffe said he thought Campbell was a "great broadcaster" and the show wasn't doing anything wrong, but people's viewing habits had changed.
He said most people arrived home from work at 7pm and wanted to be entertained, rather than watch current affairs.
"It's not that it's bad, I just think people get tired of it."
MediaWorks has denied the Jono and Ben show had been considered as a possible replacement for Campbell Live.
MediaWorks corporate counsel Alex Nicholson issued a statement today saying: "Jono and Ben has never once been mentioned in any MediaWorks management forum, discussion or document as a possible replacement for Campbell Live."
Mark Jennings added: "Campbell Live is one of the mainstays of New Zealand media and has been at the forefront of New Zealand's news and current affairs landscape for a decade. John Campbell and Campbell Live have won every award possible, broken some of the most important stories of the decade, repeatedly been voted most popular current affairs presenter and programme, and made a real difference to Kiwis' lives."
Former broadcaster and TVNZ news boss Bill Ralston said replacing Campbell with an entertainment programme would be "ludicrous" and a huge loss to the country.
"I think they're dealing with a product that they do not understand. There is a market for news and current affairs in New Zealand and there is a market for what John is doing," he said.
Lawyers at 40 paces
"The most senior management of TV3 have been gunning for John Campbell for a long while. He has been under enormous pressure and it has been lawyers, I understand, at 40 paces as they fight this one through."
MediaWorks head of news Mark Jennings said in a statement the review was being carried out to improve commercial performance of the 7pm timeslot in a changing television market and was not a reflection of the quality of Campbell Live.
"Viewer expectations in 2015 are quite different from those of 2005 - and we need to constantly review our programming to ensure we are meeting those expectations," he said.
It is understood a new soap is considered a front-runner to replace Campbell Live.
Campbell didn't address the issue on his programme last night or respond to messages today. A woman who answered the door at his central Auckland home this morning said he was at work.
Mr Ralston said he felt those at the top at TV3 were trying to draw in a younger audience by replacing Campbell Live with a more satirical programme. It is understood senior management held another meeting last night.
Not surprising
One media analyst linked recent cutbacks in television news and current affairs to Campbell Live's uncertain future.
Peter Thompson, media studies lecturer at Victoria University, told Radio New Zealand this morning that it was possible there would be no current affairs left on prime-time television, and gave warning that broadcasters would shift such programmes to weekend mornings when "no one's watching".
"If Campbell Live is not proving cost-effective according to the bean-counters then it's not surprising in the current environment that it's come under scrutiny," he said.
He didn't know whether there was any scope to move Campbell Live to a different timeslot, but said it would be a "terrible shame" to lose the programme.
"I think it has a particular brand of advocacy journalism that has made an important contribution to the range of news and current affairs in New Zealand."
A news producer at TV3, Angus Gillies, wrote on Twitter: "The news about Campbell Live feels like the beginning of the end. I produced Campbell Live in the early days of 2005 and 06. There was always ratings pressure but we felt we were making important TV."
The news comes as MediaWorks' own research commissioned from an external company showed Campbell is the nation's most preferred current affairs broadcaster, receiving approval ratings twice that of Mike Hosking and Paul Henry.
The Herald has learned the research was in TV3's target audience bracket of 25-54 year olds, but noted there was no significant difference on research against the broader population.
Meanwhile, as news of the longstanding current affairs show's possible demise emerged, NZ On Air announced it would fund a TV3 investigative journalism show called 3D Investigates to the tune of more than $500,000.
"Investigative journalism is fundamental to a strong democracy and national debate. It is becoming increasingly scarce in New Zealand due to the commercial pressures faced by broadcasters and the news media generally," said NZ On Air chief executive Jane Wrightson.
