Former federal parliamentary speaker Peter Slipper has admitted using taxi vouchers to visit wineries around Canberra but denies doing so dishonestly, a court has heard.

Slipper is facing the ACT Magistrates Court accused of misusing his parliamentary Cabcharge allowance on three occasions in 2010, before he was appointed speaker.

His defence team has told the court Slipper has made written admissions that he visited the wineries in hire cars and filled out Cabcharge vouchers.

Sorry, this video has expired Slipper faces court over Cabcharge dishonesty claims ( Elizabeth Byrne )

But the defence said it would dispute the prosecution's arguments that he behaved dishonestly, was not entitled to use the allowance on the occasions in question and that he caused a substantial risk of loss to the Commonwealth.

A police statement of facts reveals on the first occasion in January 2010, Slipper visited up to six premises including the prestigious Poachers Pantry and Clonakilla.

The total bill for the three trips is believed to be just over $900.

A hire car driver has given evidence that he drove Slipper and another man to several wineries and at the end, Slipper asked him if they could split the payment up into four amounts "because it would make processing easier".

The driver said that Slipper had appeared "flushed in the face" and the scent of alcohol became a lot stronger in the car as the day went on.

The prosecution said the driver's recollection of events was not clear but that the driver had not agreed to Slipper's request.

The court has also heard evidence from a second hire car driver, who drove Slipper to wineries on two occasions.

She told the court that at the end of the day Slipper had asked what was owed, told her how many Cabcharge vouchers to swipe and then he had filled them in.

When asked if she had ever seen Slipper affected by alcohol, the driver replied "never" and agreed that he had always been respectful and professional as a passenger.

GPS tracking data will show movement of Slipper's hire cars

The prosecution told the court that Slipper was well aware he had to be travelling on parliamentary business in order for the Government to pay for transport.

And prosecutors alleged Slipper believed the Department of Finance and Deregulation would not find out he had improperly used the card, and would pay the fares for the trips.

It is alleged Slipper visited up to six premises, including Poachers Pantry. ( ABC News: Mark Moore )

The prosecution will present evidence from 35 witnesses, mostly via statements over the six-day hearing.

A computer presentation of GPS tracking data showing the movement of the hire cars Slipper used will also be made in court.

The court heard the police investigation, dubbed Operation Portilla, began after Slipper's former staffer James Ashby reported allegations relating to Slipper's car travel.

Those allegations did not result in charges but police decided to expand their investigation and seized 270 Cabcharge vouchers used by Slipper between January 2010 and May 2012.

Charges were initially laid early last year, but there has been a long delay in bringing the case to a hearing, partly because of two legal challenges from Slipper.

The latest challenge, based on mental health concerns, was thrown out in June.

Slipper wanted the court to set aside the charges because he was suffering a major depressive disorder, which was made worse by the case.

The court previously heard he had been hospitalised several times and had been having suicidal thoughts.

Slipper believes he has been unfairly targetted and the matter should never have come to court.

Slipper lost the Queensland seat of Fisher in the 2013 election when he ran as an independent, after splitting with Coalition colleagues when he accepted Labor's offer to be Speaker in the House of Representatives.

He had held the seat on and off since 1984, first for the National Party and later for the LNP.

Slipper resigned as Speaker in October 2012 amid a sexual harassment claim, brought by his former staffer James Ashby.

Mr Ashby recently abandoned his claim against Slipper, after a two-year court battle.