EMBATTLED Sunshine Coast MP Peter Slipper has stood aside as Speaker as explosive allegations that he sexually harassed a male staffer are investigated.
Mr Slipper flew back into a political storm which now threatens the Gillard Government given the fragile balance of power in Parliament.
Former aid James Ashby, 33, has claimed Mr Slipper, 62, hired him to pursue him sexually - a claim Mr Slipper has emphatically denied.
But this afternoon, he announced he would stand aside while the criminal allegation against him is resolved.
The Daily understands that allegation relates to alleged misuse of Cabcharges.
"The allegations include both a claim of criminal behaviour and claim under civil law,'' Mr Slipper said.
"Any allegation of criminal behaviour was grave and should be dealt with in a manner that showed appropriate regard to the integrity of Australia's democratic institutions and to precedent," he said.
"As such, I believe it is appropriate for me to stand aside as Speaker while this criminal allegation is resolved.''
The allegation by former aide James Ashby was incorrect, Mr Slipper said.
"Once it is clear they are untrue I shall return to the Speakership,'' he said.
"In relation to the civil matter there will be an appropriate process that will resolve the matter in due course.''
Labor MP and Deputy Speaker, Anna Burke, will act as Speaker.
Mr Slipper, who was under mounting pressure over his travel expenses following ongoing investigations by the Sunshine Coast Daily, left the Liberals last year and struck a deal with the Gillard Government to become Speaker.
The deal allowed the government to abandon its pledge to bring about poker machine reform as pushed by independent Andrew Wilkie.
Yesterday, Mr Wilkie joined Opposition leader Tony Abbott in calling for Mr Slipper to stand aside as Speaker.
This afternoon, media crews were camped outside his Gleneagle Court home in Buderim awaiting his arrival back from the Brisbane airport after an overnight flight from Los Angeles.
In Los Angeles, a very weary looking Mr Slipper repeatedly denied the allegations which were plastered across the front page of most News Ltd papers in the country yesterday.
The Coalition turned up the pressure, saying it would push for a vote to remove Mr Slipper.
But Deputy Prime Minister Wayne Swan told the ABC's Insiders this morning it was up to Mr Slipper to decide whether to stand aside.
"I've been in Parliament a long time. I've seen allegations come and go. These are now allegations that are in legal proceedings," he said.
Independent MP Tony Windsor said Mr Slipper was entitled to the presumption of innocence.
"We do have a judicial system. We don't try people in our Parliament," he said.
"The allegations are serious, there's no doubt about that but they are not proven and everybody has that right of due process."
PETER SLIPPER'S FULL STATEMENT TODAY
Some allegations have been made against me by Mr James Ashby. I emphatically deny these allegations.
The allegations include both a claim of criminal behaviour and a claim under civil law.
Any allegation of criminal behaviour is grave and should be dealt with in a manner that shows appropriate regard to the integrity of our democratic institutions and to precedent.
As such, I believe it is appropriate for me to stand aside as Speaker while this criminal allegation is resolved.
The allegation is incorrect, and 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.