The ACT Magistrates Court on Friday heard Slipper had been in a mental health facility receiving treatment since January.

His lawyer, Trent Jones, said via telephone link that his client had been in and out of institutions on account of his mental health for an unspecified period.

Mr Jones told Chief Magistrate Lorraine Walker the defence could apply to have the criminal proceedings dismissed if an appeal to block the case in the ACT Supreme Court failed.

“[But] nothing is set in stone at this stage,” Mr Jones said.

Mr Slipper, who did not attend Friday’s mention, is accused of misusing Cabcharge vouchers to take a taxpayer-funded tour of Canberra wineries in 2010, amassing a travel bill worth about $1000.

Mr Slipper has pleaded not guilty to the three charges.

A Supreme Court judge has reserved his decision on the former federal member for the Queensland seat of Fisher’s application to stay the charges.

Lawyers for Mr Slipper say allegations he defrauded the Commonwealth should be investigated by Parliament, not the courts.

The defence team has asked Justice John Burns to permanently stay the charges because the case would violate parliamentary privilege and was an abuse of process.

But prosecutors say politicians should not always expect to be protected from criminal prosecution by parliamentary privilege.

The matter was listed for trial in December, but those proceedings have been postponed while the higher court hears Mr Slipper's challenge.

A win would effectively end the prosecution against him.

Ms Walker on Friday retained six days for hearing the criminal case in July.

The matter was relisted for mention in May.