A Canberra court on Wednesday heard that allegations of dishonesty and sexual harassment had left Mr 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 due to mental illness was thrown out of the ACT Magistrate's Court on Wednesday. It was Mr Slipper's second failed attempt to keep charges he fraudulently used cab vouchers on a Canberra wine-tasting trip thrown out of court. He has pleaded not guilty to the allegations. A six-day hearing set to start on July 21 will now 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 said Mr Slipper's suicidal thoughts were ''highly concerning'' and told him he should not feel like a ''social pariah'', because he was innocent until proven guilty.

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

Mr Slipper, who served as the 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 Mr Slipper had experienced feelings of worthlessness and hopelessness and ''ruminated endlessly on his situation''. He said Mr 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 Mr Slipper told him he had made two attempts to take his own life early last year.

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

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

Mr Slipper is fighting three charges he dishonestly used about $1000 worth of vouchers in 2010.

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