Two media heavyweights are slugging it out on the internet over claims of vendettas against politicians and bias.

On his website, media veteran and political adviser Brian Edwards has accused TV3's political editor, Duncan Garner, of having a personal vendetta against Labour MP Chris Carter which Edwards believes has spilled over into Garner's reporting.

Mr Carter recently lost his foreign affairs portfolio after overspending on his ministerial credit card for travel expenses on trips with his partner, Peter Kaiser.

In a blog in April, Edwards claimed Garner's reporting on the matter was "barely disguised homophobia" because it included images of the couple from their civil union ceremony.

He invited Garner to respond to his accusations, but he did not.

On Saturday, Edwards raised the topic again, referring to a heated exchange between Mr Carter and Garner before an Air New Zealand flight 11 months ago.

Edwards writes that Garner approached Mr Carter and said: "Travelling on the f****** taxpayer again, Chris," and that Mr Carter told him to "f*** off".

The blog says that soon after, as Garner boarded the plane in which Mr Carter was already seated, he told the MP: "I am going to f****** get you, Carter. If it takes me to Christmas I am going to f****** destroy you" - a comment allegedly overheard by Dame Margaret Bazley.

After Edwards' latest accusation, Garner, in a cutting posting to the blog, tells Edwards he is "very, very wrong".

"Your version is simply wrong on so many fronts - you expose yourself once again as a sham and a Labour Party hack. And an increasingly unemployed one at that. Why is Labour now using other 'mediatrainers' and not you?"

The Herald understands Garner's version of events is that Mr Carter provoked the exchange by calling Garner a "c***" in the Koru Club and when he boarded the plane and asked Mr Carter "what was that about?", Mr Carter told him to "f*** off".

Garner is understood to have replied: "If you want a f****** war, you'll get one."

Garner invited Labour chief whip Darren Hughes, who was travelling with Mr Carter, to give his version of events. But Mr Hughes said yesterday he would not comment.

Dame Margaret did not return a Herald phone call yesterday.

Speaking to the Herald yesterday, Garner said Mr Carter was trying to make excuses for his downfall.

"Chris Carter is feeding Brian Edwards ... he's blaming everyone else for his own demise."

TV3 director of news and current affairs Mark Jennings said he stood by Garner's version of events.

"Carter has been caught out with excessive travel expenses. He got caught with his snout in the trough and he's just going to have to deal with it. We're always going to report those stories - that's it. That's our job."

The blog was closed down yesterday after someone claiming to be Garner and referring to him as the "country's leading political commentator" made a posting by entering a mock TV3 email address when they added their views.