An Australian radio presenter has been suspended after pressing embattled Prime Minister Julia Gillard on air whether her hairdresser boyfriend Tim Mathieson is gay, as colleagues rushed to her defence.

The startling exchange came with Gillard's Labor party far behind in the polls ahead of September elections. Personal attacks are mounting against her, including a recent menu item at an opposition party fundraiser that she called "grossly sexist and offensive".

Howard Sattler, known as a shock jock for his blunt style, posed the "gay" question late Thursday after challenging Gillard to answer a series of rumours, myths and innuendos.

He suggested Mathieson, who has been Gillard's partner for seven years and is known in Australia as the "First Bloke", must be homosexual because of his line of work, although he no longer cuts hair for a living.

"Tim's gay. That's not me saying it, that's a myth," he asked her.

"Well, that's absurd," Gillard, who met Mathieson in a Melbourne hairdressing salon before becoming prime minister, responded.

"Yeah, but you hear it, he must be gay, he's a hairdresser," Sattler said.

Gillard, Australia's first women leader, accused Sattler of making generalisations about male hairdressers.

"To all the hairdressers out there, including the men who are listening, I don't think in life one can actually look at a whole profession full of different human beings and say, 'Gee we know something about every one of those human beings'," she said.

"I mean it's absurd, isn't it?"

But Sattler, who works for Fairfax Radio, pressed his case. "You can confirm that he's not?" he asked.

"Oh, Howard, don't be ridiculous, of course not," she shot back.

The Perth radio host refused to drop the matter and continued his line of questioning before Gillard told him to bring himself "back to Earth".

Management at the radio station later issued a statement saying Sattler had been suspended pending an internal inquiry while apologising to Gillard.

"Fairfax Radio management has reviewed the interview and considers that the questions posed by Mr Sattler were disrespectful and irrelevant to the political debate," it said.

"The management of Fairfax Radio also extends its sincere apologies to the prime minister and Mr Mathieson."

Gillard on Friday refused to discuss the matter but said she was worried that women and young girls may avoid public life if they face demeaning questions from the media.

"I don't want to see a message like that sent to young girls," she told reporters.

"I want young girls and women to be able to feel like they can be included in public life and not have to face questioning like the questioning I faced yesterday."

Colleagues jumped to Gillard's defence, including former prime minister and Labor Party rival Kevin Rudd who called the questioning "appalling".

"Sattler should hang his head in total shame," he said.

"What base attitude give rise to questions like that? It's just wrong, it's just wrong, it's just wrong."

The unmarried Gillard has often been the subject of comments about her gender, clothing and private life and earlier this week was the subject of a derogatory menu item at an opposition dinner.

It listed a dish called "Julia Gillard Kentucky Fried Quail: Small Breasts and Huge Thighs and A Big Red Box".

Conservative opposition leader Tony Abbott condemned the description. But the red-haired Gillard, whose comments on misogyny last year won her global acclaim, said it demonstrated a "pattern of behaviour" within Abbott's Liberal party.