Former parliamentary speaker Peter Slipper has been summonsed to face court next month for alleged breaches of federal criminal laws, further destabilising Julia Gillard's minority government in an election year.
The Australian Federal Police have not confirmed what the summons is about, but it is understood it relates to Mr Slipper's alleged misuse of travel entitlements and that the alleged offences carry a maximum five-year jail term. The Queensland MP is due to appear in the Canberra Magistrates Court on February 15, where he can expect to be formally charged.
The police statement said it was ''in relation to three offences of dishonestly causing a risk of a loss to the Commonwealth''.
If a federal MP is found guilty of a criminal offence that carries a jail term of one year or more, they are disqualified from Parliament.
This could place the government's slim majority under pressure on contentious pieces of legislation, but would not likely see it fall.
Labor currently has 76 votes to the Coalition's 74 (if Green Adam Bandt, independents Craig Thomson, Andrew Wilkie, Rob Oakeshott and Tony Windsor are counted with Labor and Bob Katter, Tony Crook and Peter Slipper are counted with the opposition).
The crime carries a penalty of a maximum five years in prison, however Fairfax Media understands that even if found guilty, Mr Slipper is very unlikely to face the maximum penalty. It is also unlikely the case would be resolved before next federal election.
On Monday, a government source played down the news of the summons, saying the offences mentioned by the AFP did not relate to Mr Ashby's claims.
It is understood they relate to three hire car trips in 2010 amounting to about $900, in which Mr Slipper - who was then a Coalition MP - travelled beyond the allowed Canberra region.
Mr Slipper stood aside as Speaker last April following accusations by his staffer James Ashby that he had misused taxi dockets, as well as separate claims he had sexually harassed Mr Ashby.
At the time, Mr Slipper said that the ''so-called criminal allegation'' of Cabcharge rorts was a ''complete fabrication''.
In May, Mr Ashby dropped the travel rorts claims to avoid any delay in the court's consideration of his civil claim of sexual harassment and discrimination.
But by then, the AFP had launched an investigation into Mr Slipper's travel use, referring material from the matter to the Office of the Commonwealth Director of Public Prosecutions in July.
A spokesman for Attorney-General Nicola Roxon on Monday said Mr Slipper was entitled to the presumption of innocence, and prejudicial comment had to be avoided to ensure he got a fair trial.
Last month, the Federal Court threw out Mr Ashby's sexual harassment claim. In a scathing judgment, Justice Steve Rares found that the case was an ''abuse of process''.
Fairfax Media has contacted Mr Slipper.
In Brisbane on Tuesday, Opposition Leader Tony Abbott said the latest development involving Mr Slipper again exposed Prime Minister Julia Gillard's lack of judgement.
"Why did the prime minister ever think that the gentleman in question was fit and proper to be the Speaker of our country?" had said.
Mr Abbott said it was up to Mr Slipper to decide if he should resign from the parliament.
With BIANCA HALL, AAP
Correction: The original version of this story referred to the offences being related to Comcar trips in 2010, rather than hire car trips.