Campbell Live last night beat the TV One 7pm show Seven Sharp overall audience for the first time since Campbell Live began in 2005.
It is also the first time TV3 has ever beaten TV One in the 7pm weekday slot since TV3 began in November 1989.
Seven Sharp took another hit in the ratings on Tuesday night after a short recovery in Monday's show, according to overnight ratings from Nielsen TAM.
The overnight ratings are significant, with Seven Sharp last night providing the most accomplished performance so far. Fewer people would have seen the signs of improvement on the show.
The audience for people aged over five years is an indicator of the total audience, which is dominated by TV One . Last night's ratings illustrate the danger that older Seven Sharp's viewers - carried over by its predecessor, Close Up - are migrating to Campbell Live.
The ratings figures from Nielsen TAM figures for Tuesday back up indications it is not reaching the younger viewers it is targeting with its focus on social media.
Campbell Live last night had 352,600 viewers compared to 296,700 for Seven Sharp.
It is the smallest audience for Seven Sharp since it began on February 4. In the demographic for people aged 25-54 - the target demographic for TV3 and TV One - Campbell Live had 127,600 viewers compared to 99,100 for Seven Sharp.
In the 18-39 age group Campbell Live had 55,500 compared to 40,800 for Seven Sharp according to the rating figures.
The TVNZ head of news and current affairs Ross Dagan, who was the architect for the show, has said it is too early to judge ratings for Seven Sharp.
In a statement posted on Throng.co.nz, TV3 director of news and current affairs Mark Jennings said "once over lightly" was not their style.
"For us, in-depth daily coverage of the stories and issues that matter to Kiwis is central to the future of current affairs. Viewers are clearly telling us this is what they want; substance and not once over lightly."