Heather du Plessis-Allan will begin hosting TV3's new current affairs show, Story, in six weeks' time, alongside Duncan Garner.
But the former Seven Sharp reporter will remain in the political gallery reporting for TVNZ for the next four weeks.
TVNZ confirmed du Plessis-Allan will see out her notice with the company and has not been "walked" as is common practice in the media industry when employees defect to competing organisations.
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A TVNZ spokesperson said: "I can confirm that Heather will be working out her notice period at TVNZ and that we will shortly commence looking for a political journalist to join our Wellington-based press gallery team."
Former TVNZ news boss Bill Ralston says it could be a deliberate strategy by the state broadcaster.
"If TVNZ wanted to slow down the launch of the programme, they could hold on to her for that four-week period," he said. "Otherwise she would have four weeks to go over there and get stuff together.
"If she was fronting Seven Sharp, you would take her off air immediately because you wouldn't want her keeping her profile up."
But he says it's not unusual to make people work out their notice.
"In my time, it was probably about 50/50. If I thought they were being disruptive in the newsroom or it was 'good riddance', you'd let them go straight away."
But, sources have told the Herald, senior staff in the TVNZ newsroom are unhappy with the decision made by their boss, John Gillespie.
It's understood du Plessis-Allan had assured colleagues she was staying with the network, before yesterday's announcement.
The new presenter and her co-host Garner will have a major challenge winning back viewers, as Seven Sharp's ratings continue to grow in the absence of any current affairs competition on TV3.
A Herald poll of more than 1700 people found 67 per cent wanted Campbell Live to return, while 15 per cent say they are Seven Sharp converts. Just 11 per cent said they liked the sound of Story.