A Canberra court heard on Wednesday that allegations of dishonesty and sexual harassment had left Slipper feeling he had no way out and had driven him to try to take his own life.

Yet his application for the charges to be dismissed because of mental illness was thrown out of the ACT Magistrate's Court.

It was Slipper's second failed attempt to keep charges he fraudulently used cab vouchers on a Canberra wine-tasting tour out of court.

He has pleaded not guilty to the allegations.

The decision means a six-day hearing set for July 21 will go ahead.

In handing down her decision, Chief Magistrate Lorraine Walker acknowledged the defendant had been diagnosed with a major depressive illness and swift resolution of the legal matters would be in his interests.

She told the court Slipper's suicidal thoughts were ''highly concerning'' and told him he should not feel like a ''social pariah'' because he was innocent until proved guilty.

Although the amount of money related to the offences was relatively small, Slipper's position as a federal MP at the time meant they were potentially serious, she said.

Slipper, who served as speaker in 2011 and 2012, appeared in court on Wednesday with a cast on his right arm.

His treating psychiatrist Christopher Martin said via audiovisual link that Slipper had experienced feelings of worthlessness and hopelessness and "ruminated endlessly on his situation" during the past year.

He said Slipper used alcohol to deal with his problems and had "a sense that he has no way out of his current predicament".

Dr Martin said Slipper told him he had made two attempts to take his own life early last year.

The psychiatrist said in a report his patient had become a "social pariah" and had withdrawn from personal relationships. He also rarely went out because he feared public recognition and ridicule.

His ''very public fall from grace'' had left the former speaker ''functionally more or less disabled'', Dr Martin said.

The court heard Slipper had been admitted to a medical facility for treatment on five occasions since May last year, for periods of between five days and almost a month.

Crown prosecutor Lionel Robberds, QC, argued that Slipper's mental state had deteriorated after the offences took place and that it had not affected his cognitive function.

Slipper is fighting three charges he dishonestly used about $1000 worth of Cabcharge vouchers to take a taxpayer-funded wine-tasting tour of Canberra in 2010.

Slipper's defence barrister, Kylie Weston-Scheuber, applied to have the charges dropped on mental health grounds following a failed bid last month to permanently stay the charges.

Former political staff member James Ashby last week dropped a sexual harassment case against Mr Slipper, which was due to be back in court on Friday.

Support is available for anyone who may be distressed by calling SANE Helpline 1800 18 7263; Lifeline 131 114; Salvo Crisis Line 9331 2000; beyondblue 1300 22 46 36.