There's no room for stigma when it comes to GPs prescribing a safe sex drug commonly used by gay men, a leading doctor says.

Pre-exposure prophylaxis is up to 99 per cent effective in preventing HIV, and this week Pharmac announced it was overhauling the criteria for funded prescriptions of the drug.

However, safe sex advocates say doctors need to be more confident about prescribing it, some patients face stigma from doctors when trying to get a prescription, and they want to see LGBQTIA+ healthcare improve.

From July 1 this year, some previous criteria for a funded prescription has been removed, including a strongly criticised stipulation that the patient had had unprotected receptive anal sex with a casual partner in the previous three months.

Instead, it now required that the patient be at risk of, but tested negative for HIV, and that their doctor believed it was "clinically appropriate" for them.

HIV peer support organisation Body Positive executive director Mark Fisher says a lot of work has been done to raise awareness of the drug, but more is needed.

"PrEP stigma is a thing that's still out there.

"We need to normalise it, so it needs to become like viagra or the contraceptive pill."

He says clients of his organisation have been unable to get prescriptions because their GP did not "feel comfortable" prescribing it.

Similar experiences are highlighted by sexual health researcher Peter Saxton (who was leading the Sex and Prevention of Transmission Study), in his submission to Pharmac about the criteria change.

University of Auckland researcher Dr Peter Saxton Photo: RNZ / Jake McKee.

He used unpublished data from the study, which included comments about a nurse saying "how all gay and bisexual men should stop being promiscuous" when someone mentioned wanting to be on PrEP, a GP telling another person "it was disgusting" and they "should just use a condom", and others feeling judged.

Royal College of GPs medical director Bryan Betty says such experiences "would be a very unusual situation", and should not happen.

"Basically, general practitioners who are professionally trained and vocationally registered are trained to take a non-judgemental approach to patients - and that would be the expectation of the College."

Dr Bryan Betty Photo: RNZ / Karen Brown.

He says there is "freely available" training online for medical professionals to upskill and educate themselves around PrEP.

Betty says Pharmac's changes will help more medical professionals become aware of the drug as more patients get prescriptions.

-RNZ/Jake McKee.