As Mr Abbott today denied there was a Coalition conspiracy, Ms Gillard said Mr Abbott had to stop using ''weasel'' words over the matter and disendorse the Liberal National Party candidacy of Mal Brough - who the Federal Court found worked with James Ashby to harm Mr Slipper.

In an interview with ABC Radio on Friday, Ms Gillard also repeated Labor calls for Mr Brough to come to Canberra to answer questions from the federal parliamentary press gallery about his role in the Slipper case.

"And then [Mr Abbott] should still disendorse Mr Brough," Ms Gillard said.

"Mr Brough has been anything but transparent in this matter ... Mr Brough has been involved in using sexual harassment claims as a political tool."

Ms Gillard said that in standing by Mr Brough, Mr Abbott was also standing by "conduct like this".

The Prime Minister also called on other Coalition members to clarify what they knew about James Ashby’s allegations against his former boss, Mr Slipper, before they were first aired in the media.

"What did Mr Abbott know? What did his office know? What did Ms Bishop know? What did Mr Pyne know? What did Mr Hockey know? Who else is involved in this conspiracy? What were their motivations in using sexual harassment as a political tool of attack?"

No Coalition conspiracy: Abbott

Earlier, Mr Abbott addressed the media for the first time since allegations against Mr Slipper were dismissed by a federal court judge on Wednesday. Speaking from London, he insisted there was no coalition conspiracy linked to the sexual harassment claim against Mr Slipper.

Mr Abbott also again denied having any knowledge of LNP involvement in the case.

"The Labor party should accept that there are no conspiracies here; there are no conspiracies whatsoever," Mr Abbott told reporters.

"I think the Labor Party should stop hyperventilating. If the Labor Party thinks there’s been some terrible injustice done to Mr Slipper, they should put him back into the Speaker’s chair."

Mr Abbott said he would stand alongside his parliamentary colleagues in supporting Mr Brough, a former Howard government minister, who was named in the court judgment as having worked in "combination" with Mr Ashby and a fellow staffer to bring about the sexual harassment case in order to damage Mr Slipper.

Brough to stay as LNP candidate

He further confirmed Mr Brough as the LNP candidate for Fisher, Mr Slipper’s current seat, in the 2013 election.

"I think that Mal Brough was perfectly and properly endorsed by the Liberal National Party. He’s been quite transparent and up front about his involvement and, as I said, the matter is now subject to appeal," the Opposition Leader said.

On Wednesday, Federal Court Justice Steven Rares dismissed a sexual harassment claim by Mr Slipper’s former staffer, Mr Ashby, saying the matter was an abuse of process with the main purpose of pursuing "a political attack" on the member for the Queensland seat of Fisher.

Asked about his involvement in the case against Mr Slipper, Mr Abbott replied "none whatsoever", and also denied knowledge of any role played by his federal coalition members.

"There are all sorts of rumours that have been running around about Mr Slipper for years," Mr Abbott said. "Those rumours intensified in the weeks leading up to the court case or the lodgement of a claim against him."

The Opposition Leader insisted he had no "specific knowledge" of the matter until it broke as a newspaper story on April 21 this year.

Mr Abbott also rejected Labor Party plans for an inquiry into the Coalition’s involvement in the sexual harassment claim.

"I think any such inquiry would plainly be a bit of a witch-hunt," he said.

Anna Burke to stay as Speaker

Ms Gillard said the government would not rush to judgment about whether an inquiry was needed into the Slipper matter: "we will think about it." But she reaffirmed Labor’s support for current speaker, Anna Burke, saying Ms Burke would continue in the role.

"Mr Slipper resigned appropriately," Ms Gillard said, referring to his resignation over a series of lewd text messages in October.

Ms Gillard said that Mr Abbott has never accepted the result of the 2010 election and so Australia had been "treated to two years of negativity".

"I would like to see this cycle of politics about sleaze and smear and negativity - the cycle Mr Abbott started the day after the last election - come to an end and come to end before the end of this year," Ms Gillard said.

Bishop's office contacted by Ashby

Deputy Opposition Leader Julie Bishop told Sky News on Friday she had "no personal involvement" in the Slipper matter and had never met Mr Ashby or taken a phone call from him. However, her staff had been in contact with him before the case was lodged in April this year.

"About a month before the story broke [in April] he contacted my office," Ms Bishop said. "He spoke to one of my staff and said that he had workplace harassment issues with Mr Slipper and my staff advised him to seek advice from the Department of Finance [as the ultimate employer of MPs' staff]."

Mr Abbott is in London for five days, during which he will meet British Foreign Secretary William Hague, Bank of England Governor Mervyn King and Mayor of London Boris Johnson.

With AAP