Photo: Graham Perrett has asked the Federal Police to determine if Mal Brough breached the Crimes Act. (AAP: Alan Porritt)

A Federal Labor MP has asked the Australian Federal Police to investigate the involvement of key Liberal Party figures in the Peter Slipper sexual harassment case.

The Federal Court found the failed case was brought by Mr Slipper's former staffer James Ashby to further the interests of former Howard minister Mal Brough, who is the Liberal National Party candidate for Mr Slipper's seat.

Queensland Labor MP Graham Perrett says he has written to AFP Commissioner Tony Negus, asking him to investigate if the Liberals used the sexual harassment claim to harm Mr Slipper and the Government.

The Liberals named in the letter include former minister Mal Brough, Opposition frontbenchers Christopher Pyne and Julie Bishop, and Queensland state minister Mark McArdle.

"If they run the ruler over it and Mr Brough and Mr Pyne and Ms Bishop and Mr McArdle, et cetera are all found to have not committed a criminal act, or have not committed a criminal act that is worth pursuing by the DPP, well so be it," he told ABC radio.

Mr Perrett says he also wants the commissioner to investigate if Mr Brough asked Mr Slipper's staffers to provide unauthorised access to the former speaker's official diary.

He is asking whether Mr Brough breached the Crimes Act by leaking sensitive information in a bid to improve his chances of winning Mr Slipper's seat.

"People have been so obsessed on grabbing political power that they've forgotten about the laws," he said.

Mr Perrett says emails that came to light during the Federal Court case indicated Mr Brough continued "to play a central role in coordinating the plot against Mr Slipper up until the point at which the sexual harassment claim was filed".

"I request that the Australian Federal Police conduct a formal investigation into this information, to determine whether any criminal offences have occurred," he wrote in the letter.

"This conspiracy involved using a fabricated sexual harassment claim to politically damage and publically humiliate Mr Slipper ... designed to inflict such significant reputational, psychological and emotion harm to [him] so as to cause him to resign as both the Speaker of the House of Representatives and the Member for Fisher."

But Opposition frontbencher Greg Hunt has told Sky News that Mr Brough did nothing wrong.

"I have not just read the judgement, but also read the texts, and the idea that somebody should not have referred a sexual harassment allegation to a lawyer is preposterous," he said.

"What Mr Brough did is exactly the right thing."

Opposition Leader Tony Abbott says he is concerned the Government is investing time and money in a useless attack.

"Has any taxpayer money been used to prepare this letter? Have public servants been used to prepare this letter? Did Mr Perrett actually author this letter himself?" he said.

Mr Abbott says any investigation will clear Mr Brough's name.

"They should get over it. They should accept that there has been no conspiracy here," he said.

"They should understand that the only real issue when it comes to Peter Slipper is that why did the Prime Minister ever think that he was a fit and proper person."

Labor MP asks AFP to investigate Brough - ABC News (Australian Broadcasting Corporation)