Lawyer-turned-informer Nicola Gobbo will instead be forced to give evidence at a royal commission into police informers in January despite claiming she is too sick.

"The commission is willing to take her evidence over short periods, by telephone to accommodate her medical conditions," Commissioner Margaret McMurdo said on Wednesday.

The commission was set up after it was revealed Ms Gobbo told police about the activities of her underworld clients while she was acting for them.

Ms Gobbo was ordered to give evidence via telephone on January 29, 2020 - but the commissioner later said she didn't expect the lawyer to actually do it.

"I have no confidence that ultimately Nicola Gobbo will give evidence before this commission, whether or not she eventually provides a reasonable excuse for not doing so," Ms McMurdo said.

While the commissioner noted she previously accepted Ms Gobbo had a reasonable excuse for not giving evidence, she noted there had been "ample time" for the disgraced lawyer to adjust to her changed circumstances.

Barrister Rishi Nathwani had argued Ms Gobbo's poor mental and physical health, risk to her life and poor memory were a "reasonable excuse" for her not to give evidence.

"She cries most days and feels her brain cannot function normally," a mental health specialist said of Ms Gobbo in a report read out at the inquiry.

Mr Nathwani said she was in considerable pain, needed medication and her mental state had deteriorated in the past year.

The revelation she was Lawyer X led to a "dramatic change" in her health and it had placed her life in more danger, he said.

Another report stated she was not responding to medical intervention and was at risk of a "psychotic" breakdown.

Ms Gobbo also suffered from memory loss and poor concentration that would leave her unable to prepare for questioning, her lawyer said.

In the past 10 months she has not gone through any of the transcripts from the commission.

Another expert said Ms Gobbo experiences "rage and fear" about her treatment at the hands of the police.

But counsel assisting Andrew Woods said Lawyer X could give evidence over the phone for short periods. He said she'd given evidence in court in 2017 despite concerns over her health.

Ms McMurdo also said the medical opinions were based on how accurate Ms Gobbo was with her doctors.

"In evidence before this commission she told her handlers of her preparedness to falsely use her medical conditions to mislead the court to improperly obtain an adjournment of a case to suit her own needs," Ms McMurdo said.

Nicola Gobbo was first registered as an informer for Victoria Police in 1995 while she was a university student and then again in 1999.

Though the commission cannot force her to give evidence a failure to comply with an order is a criminal offence with a maximum penalty of two years in jail.

Australian Associated Press