Slipper faced the ACT Magistrates Court on Monday to fight accusations he dishonestly used about $1000 worth of cab vouchers for three separate hire car trips in 2010.

The former Queensland MP has pleaded not guilty to all three fraud charges brought against him.

Slipper made two failed attempts to have the case thrown out of court but now faces a hearing, which was set down for six days, before Chief Magistrate Lorraine Walker.

In his opening address, prosecutor Lionel Robberds, QC, said Slipper had used taxpayer-funded Cabcharge dockets to pay for the three trips between January and June 2010.

"It is alleged these trips were made by the defendant on personal business and he knew that he was not allowed to use his Cabcharge vouchers on such business," Mr Robberds said.

The court heard Slipper

He requested to pay hire car drivers for the trips manually with the vouchers, rather than the electronic method the Finance Department preferred.

Slipper made several written admissions concerning the trips, including the places he visited, the time he spent at each location, and the way he paid for the trips, the court heard.

His defence barrister, Kylie Weston-Scheuber, said those matters were "not in dispute".

Dr Weston-Scheuber said the court needed to determine whether there was any evidence Slipper had knowingly defrauded the Commonwealth, or had acted dishonestly on any of the occasions.

The court heard the hire cars used for the trips were fitted with GPS devices which tracked their location.

A Google Maps presentation outlining the routes taken on the three trips was shown in court.

One hire car driver told the court he had taken Slipper and a male guest, who he understood to be a colleague, to a series of wineries in the Murrambateman area, including Clonakilla and Poachers Pantry, in 2010.

The driver said the two passengers had smelled strongly of alcohol as the tour progressed, and Slipper "appeared flushed in the face".

Slipper had asked to pay for the trip manually using the vouchers and for it to be split into four separate trips, the driver said.

The driver said he hadn't recalled the trip when first approached by police, but later remembered it "because it was unusual".

It had been the first time a client had asked for a trip to be split into four as usually they paid the full amount as one trip at the end of the day, he said.

A second driver told the court she had driven Slipper on numerous occasions and it was common for him to keep a running tab and then use multiple vouchers to pay for his trips.

''I asked him for a total at the end of the day, asked how many vouchers to swipe and I put the payment through,'' she said.

The driver said Slipper was the only client she knew of who paid in that way.

The court heard the initial investigation into Slipper's travel entitlements had been prompted by allegations brought by former political staffer James Ashby about car trips in 2012.

No charges were laid as a result of that investigation, however senior police had decided to broaden the investigation to cover a period of more than two years.

Australian Federal Police agent Jeffrey Pearce said officers seized about 270 of Slipper's Cabcharge vouchers and visited Canberra region wineries as part of Operation Portilla in 2012.

Slipper, a Liberal-turned independent who served as parliamentary speaker in 2011 and 2012, was quiet and sat alone during the first day of the hearing.

He lost two previous bids to have the case thrown out of court, most recently on mental health grounds.

An unrelated sexual harassment claim against Slipper, taken out by Mr Ashby, was dropped last month.

The hearing continues.