DESPITE withdrawing her comments, Michaelia Cash won't apologise for threatening to expose rumours about Bill Shorten's female staffers and isn't being asked to do so by the prime minister.

Senator Cash erupted during a fiery Senate hearing on Wednesday with a pointed warning she would "name every young woman" in the opposition leader's office about whom rumours had circulated.

She "unreservedly" withdrew the comments on Thursday, but Mr Shorten said he was still waiting for a phone call and an apology.

"I'm honestly shocked she hasn't said sorry. I've been waiting for her to ring up my office and organise it," Mr Shorten said in a statement on Thursday.

"The prime minister said a few weeks ago that the parliament needed to be a more respectful workplace for women. I agree with him. Maybe he should try doing something about it."

But Malcolm Turnbull backed his minister when asked if he would make her say sorry.

"Senator Cash was being bullied and provoked by Senator (Doug) Cameron who was making insinuations about staff," he told parliament.

"She made a response which she has unreservedly withdrawn."

Today host Ben Fordham said on Friday that Senator Cash was "juvenile" for withdrawing the comment but not saying sorry.

"How juvenile when you've got Michaelia Cash saying 'I unreservedly withdraw' but she can't say the word 'Sorry'. Come on," he said.

Liberal frontbencher Christopher Pyne said if Senator Cash apologises, then Labor Senator Kim Carr should also say sorry about likening Liberal Senator James Paterson to a "Hitler Youth".

But Labor frontbencher Anthony Albanese said Senator Carr had already apologised for the comments.

"He went straight back into the Senate and apologised yesterday, as he should have. Michaelia Cash should have just simply apologised," Mr Albanese told Today.

"The problem here is that these issues go for far too long, they are a huge distraction and quite frankly it's not good enough."

Jobs Minister Michaelia Cash hides behind a white screen on her way to Senate estimates.
Jobs Minister Michaelia Cash hides behind a white screen on her way to Senate estimates.

'I WITHDRAW THE REMARKS'

Senator Cash said after pressure from Labor to apologise on Wednesday: "If anyone has been offended by my remarks, I withdraw."

On Thursday, Senator Cash told a hearing she "unreservedly" withdrew the comments, but accused Senator Cameron of making insinuations about her staff.

"I'm more than happy to withdraw them unreservedly," she said.

Labor frontbencher Brendan O'Connor said withdrawing the comments wasn't good enough.

"Minister Cash must do two things today - apologise and then resign," Mr O'Connor told reporters.

"She needs to apologise for the slanderous slur she made yesterday towards young women working in parliament."

Appearing to try to avoid scrutiny from the media, Senator Cash entered a Senate estimates hearing on Thursday behind a whiteboard to shield her from cameras.

Mr Pyne said the whiteboards should be "put away".

"I don't know whose idea that was, we had the white board once before in federal politics and people should put white boards away and go through the normal process," he said.

Deputy Labor leader Tanya Plibersek demanded Senator Cash look Mr Shorten's staff in the eyes and say she was sorry.

But cabinet minister Peter Dutton appeared to add fuel to the fire by saying it "was a bit rich" for Labor to be "moralising" on the coalition. "I think Mr Shorten has demonstrated on a number of occasions in relation to many issues that he is not a genuine person and he shouldn't be taken at face value," Mr Dutton said.

Mr Dutton declined to expand on what he meant by his remarks about Mr Shorten. Wednesday's heated exchange occurred as Labor continued to pressure Senator Cash over raids at Australian Workers' Union offices last October. Details of the police raids were leaked to a TV network by one of her media advisers, who later quit.

Cabinet minister Michael Keenan repeatedly denied his office having any role in the leak, under questioning from Labor MPs in parliament.

Buzzfeed reported a journalist claimed they received a tip-off from the former justice minister's office ahead of the raids.

- With AAP