The findings of research, funded by the New Zealand AIDS Foundation (NZAF), were published in the New Zealand Medical Journal today.

New Zealand became one of the first countries in the world to publicly fund PrEP in March 2018, for men who have sex with men, or transgender people, who meet the eligibility criteria.

This criteria included those who engage in sexual activity without condoms being consistently used, or people who had a regular sexual partner who was HIV positive.

According to Pharmac, 700-900 people were taking the drug, but this only makes up a small proportion of the approximately 5800 who were eligible.

Research author Peter Saxton from the University of Auckland said one of the most critical concerns was the prescribing bottleneck.

"At the moment PrEP can only be approved from one of around 45 HIV specialists in the country and repeat prescriptions can be given by nurse practitioners and GPs who have gone through an accredited course.

"It just means at the moment the range of people who can prescribe PrEP is really limited," he said.

Dr Saxton said if all those eligible took the pill, this would equate to around 29,000 clinic appointments every year, half of which would be in Auckland.

"That really is a challenge to the health system, sexual health clinics themselves clearly can't cope with that volume," he said. Read more via Radio NZ