The Speaker of Australia’s House of Representatives, Rt Hon Peter Slipper, has stepped down from his parliamentary position, over allegations that he sexually harassed a male staff member, and misused publicly-funded Cabcharges.

The allegations, first reported by newspapers of Murdoch-owned News Limited, now have the potential to bring down Julia Gillard’s minority government, it is reported.

James Ashby, 33, petitioned a Federal Court yesterday claiming that he was continually harassed by Mr Slipper since he began working for him since December 2011. He alleges that Mr Slipper recruited him solely “for the purpose of pursuing a sexual relationship.”

In his petition, Mr Ashby claims to have been open about his own homosexuality from the very beginning. In the very first weeks on the job, Mr Slipper, who is married with two adult children, is alleged to have requested massages, asked him for graphic details on his sex life, and sent him sexually suggestive text messages.

Mr Ashby, who has until now been known best for grabbing a journalist’s mobile phone at one of Mr Slipper’s press conferences and throwing it away, alleges that his employer always sent him texts signed with an ‘x’ or an ‘xxx’, and that he was once asked by the 62-year-old to shower with the bathroom door open. At another instance, Mr Slipper is supposed to have asked the younger employee whether he preferred “twinks” or “bears.”

News Limited papers also report that the government under John Howard was aware of Mr Slipper’s sexual relationship with another young male adviser, along with other allegations of sexual harassment, as early as 2003.

Mr Slipper had not yet returned to Australia from a trip abroad when the news broke, and did not respond to questions put forth by journalists at a Los Angeles airport. He merely repeated the words he put on his Twitter account, saying: “All allegations are denied.”

Now, on returning to Australia, he released a statement “emphatically” denying the allegations. “The allegations include both a claim of criminal behaviour and a claim under civil law,” he said. “As such, I believe it is appropriate for me to stand aside as Speaker while this criminal allegation is resolved. Once it is clear they are untrue I shall return to the Speakership. In relation to the civil matter, there will be an appropriate process that will resolve the matter in due course.”

He will be temporarily replaced by his deputy, Labor MP Anna Burke.

Mr Slipper defected from the opposition Liberal Party last November, in order to take his position as the Speaker. Should he resign, that would take away the slim majority Ms Gillard holds, leaving her vulnerable to a vote of no confidence.

The case is due for hearing at the Federal Court on May 21.