Radio New Zealand's Morning Report host Sean Plunket says he is "moving on and looking for a new job" after 11 years with state radio.

Radio New Zealand insiders said that difficult relations with RNZ boss Peter Cavanagh had come to a head when the CEO banned him from hosting tonight's pre-election debate about the internet on TVNZ 7 Freeview.

Political commentators typically swap around media for special shows in the run-up to elections.

But an insider said that the row went beyond that and on to plans for Plunket.

"They want him to be the new Geoff," said the source.

Plunket's co-host Geoff Robinson is expected to move on soon.

Plunket - who is arguably New Zealand's toughest broadcasting interviewer and famous for taking politicians to task - said that after 11 years he was looking for a role that had a new spark. He had not resigned yet.

"I'm putting my portfolio together and I'll be taking my time," he said.

TVNZ 7, a digital information channel available on Freeview, confirmed that Plunket pulled out of hosting tonight's internet debate suddenly at the weekend.

"But that is a matter between him and Radio New Zealand," said TVNZ 7 management. Blogger and journalist Damian Christie was assigned to the programme at short notice. Plunket would not discuss the demand that he pull out of tonight's internet debate.

A Radio New Zealand source said Mr Cavanagh was insistent Plunket could not have a role outside RNZ.

Plunket said there was nothing in his employment contract that limited his hosting special events for other media.

The TVNZ 7 audience is tiny and a high-profile presenter like Plunket would attract viewers. But Mr Cavanagh is said to be wary about boosting TVNZ 7 and has stopped other freelancers from working for the new Freeview channel.

It is understood he fears that as TVNZ 7's audience grows it will undermine RNZ's role as a centre of public debate.

By John Drinnan @Zagzigger Email John