Fairfax radio presenter Howard Sattler says he is planning legal action after he was sacked for asking Prime Minister Julia Gillard if her partner Tim Mathieson is gay.

Sattler asked the question during an interview on Fairfax Radio's 6PR on Thursday, in which he challenged Ms Gillard to address a series of myths and rumours.

Ms Gillard said the line of questioning was absurd.

Sattler was stood down on Friday morning before 6PR general manager Martin Boylen announced on air about 2:30pm (AWST) that he had been sacked.

"In the wake of yesterday's interview, radio 6PR suspended Mr Sattler from broadcasting, pending a review of the matter today," he said on Friday.

"The station has now decided to terminate Mr Sattler's engagement, effective immediately."

Sattler had six months remaining on a two-year contract and said he is planning to take legal action over the termination.

Speaking to media immediately after the announcement, Sattler said he was "staggered" and "flabbergasted" by the action.

But he said there were other factors at play in his sacking.

"I believe that the reason given is not the only reason for this happening," he said.

"It is unjustified and in my belief it is possibly unlawful what they've done.

"I'll be taking the matter further. I'll be exercising all my lawful rights to vigorously pursue any and all of my entitlements."

Late last year complaints were made to the station about Sattler slurring on air, with some people saying he sounded drunk.

He announced publicly that he had had at least one stroke.

Sattler then announced in March this year that he had been diagnosed with Parkinson's disease.

He refused to comment on Friday on whether he believed this had been a factor in the termination of his contract.

'She agreed to stop me if it went too far'

Sattler said he had no regrets over the incident.

"She should have known it was coming," he said.

"She agreed she'd stop me at any stage if it went too far."

Sattler said his producers had briefed Ms Gillard's office about the intended line of questioning prior to the interview.

"They confirmed that in an email they sent to me at 8:59am yesterday that it was a candid interview," he said.

"In the preparation for the interview my producers talked about how we were able to talk about her personal feelings about same-sex marriage, the fact that she's not married and why not and all this sort of thing.

"The interesting thing is that after the interview she happily agreed to be in a photograph with me."

Radio station 'unreservedly' apologises

The station has released a statement apologising "unreservedly" for the incident.

"During an interview on the Drive program yesterday, presenter Howard Sattler pursued a line of questioning with Prime Minister Julia Gillard that was disrespectful to the office and person of the Prime Minister and was entirely inappropriate," the statement read.

"Radio 6PR apologises unreservedly to Ms Gillard and Mr Mathieson for allowing these matters to be raised."

Federal Opposition leader Tony Abbott has also spoken out about Sattler's questioning.

"It was a very poor thing to say. I condemn it," he said.

"You shouldn't harass public figures like this, and that's all it was, just harassment."

This is how the interview played out on Thursday: