"People are semi-evenly choosing between these two programmes and that doesn't entirely surprise me.
"What's interested me is that I've started to find the lighter touch of Seven Sharp a little bit appealing and I sort of watch it and there's a few laughs and giggles. It's not demanding in any way.
"If you go across to John Campbell it's quite a demanding programme, pretty serious. I think now we may be seeing viewers getting sort of a choice here - do you want light bright and breezy, or do you want serious?"
A "huge" fan of Campbell, Dr Edwards said overall the results were a win for TV3 because traditionally its six o'clock news delivered significantly less viewers to 7pm than its rival. But he said producers may want to look at its "preachy" tone which long-term might drive viewers away.
TV3's Director of News and Current Affairs for TV3 Mark Jennings said it was difficult to get people to switch news or current affairs programmes.
"It is an area of great loyalty and viewers are highly tolerant. In my 24 years at TV3 it has happened twice - once when John Hawkesby defected to TV One and again when One News forced Judy Bailey out. On those occasions the audience were upset enough to switch to 3 News and many of them stayed. Now I think it is happening for a third time.
"Seven Sharp doesn't seem to know who it is aiming at. They say they are trying to present current affairs in an entertaining way ... fine, but the problem here is that it seems to be neither informative or funny."
Neither TVNZ's head of news and current affairs Ross Dagan or chief executive Kevin Kenrick were available for an interview.
Communications manager Megan Richards said no sensible conclusions could be drawn from ratings and "until everybody calms down there's little point in trying to explain the consumer behaviour that led us to move away from 'traditional' current affairs at 7pm. We need to give people time to get used to a different approach, and we hope people will give us time to settle in to a new show".