Seven Sharp, a departure from the more straight current affairs format of its Close Up predecessor, was watched by 508,500 viewers on Monday night.
That number steadily fell during the week, with 310,300 tuning in on Thursday night, according to ratings figures supplied by NielsenTAM.
The number of people deserting the show from its lead-in, One News, jumped up to 52 per cent, Throng.co.nz reported yesterday.
Campbell Live on TV3 was watched by 265,000 on Thursday. Its ratings have been steady throughout the week.
TVNZ's new current affairs show has been put under a microscope by critics and social media since its much-anticipated debut on Monday.
Attempts to blend serious news items with satirical jokes, host "banter" and viewer interaction have been panned by those hoping for more serious content.
Mr Dagan said there was a core of media and viewers who had made up their minds about the show before seeing it.
"I don't think anyone thought that a few days on air would have them change their minds publicly ... fundamentally we are flattered with all the interest."
Each show would be examined and changes made if deemed necessary, Mr Dagan said.
"We have taken the decision to provide a different future for current affairs, and we think we are absolutely on the right track."
The drop in Seven Sharp ratings has not translated into a boost for Campbell Live, with viewership of the TV3 show remaining relatively steady.
In the 25-54 age group - the target market for TV One and TV3 - Campbell Live was watched by 78,600 people on Thursday night, down from 87,400 viewers on Monday.
Seven Sharp rated 64,400 viewers in the age group, down from 131,300 on Monday night.
Last year Close Up, hosted by Mark Sainsbury, averaged 456,000 viewers a night.
