A Perth magistrate has refused to grant bail to a transgender sex worker because she refuses to accept she has HIV and may put other people at risk if she is released.

Clayton James Palmer, who identifies as Sienna Fox, is facing a charge of causing grievous bodily harm to a client, whom it is alleged she infected with HIV after several sexual encounters in 2015.

Ms Fox is currently being held in the high-security Casuarina male prison, but today her lawyer Simon Freitag applied for her release on bail.

Mr Freitag provided the Perth Magistrates Court with a report from an expert on transgender issues, which he said had found the male prison was "potentially a very harmful place" for his "vulnerable" client.

Mr Freitag said Ms Fox was being held in a crisis care unit and her access to social interaction and recreation was restricted, putting her mental health and wellbeing at risk.

He said while Ms Fox does not accept that she has HIV, she would be better able to receive counselling and treatment for her health issues if she was in the community.

He said the defence's "fallback" position was that Ms Fox be held in Bandyup women's prison.

The bail application was opposed by the police prosecutor, Senior Constable Jarred Gerace, who told the court it was alleged Ms Fox falsely told the man with whom she was having sex that she had no health problems and was regularly being tested.

Senior Constable Gerace said Ms Fox also continued to advertise for sexual services after she was diagnosed with HIV and also refused to undergo any follow up treatment.

Magistrate Andrew Maughan said his main concern was Ms Fox's denial that she has HIV and the risk she may engage in further sexual work if she is released.

"The risk that she poses of endangering the safety of other people is not a matter that can be overcome by any bail conditions."

Mr Maughan described the situation as "unfortunate" and urged that a copy of the expert report provided to him by the defence be made available to the prison authorities who determine where Ms Fox should be kept.

Ms Fox was extradited from New South Wales in February.

She is due back in court in July.