"HIV-HIV-HIV. How am I going to tell my parents I'm HIV positive?" The thought consumed him the morning after a night of unprotected sex.

To his relief he had not contracted the virus, but that anxiety is a constant passenger for many sexually active gay men.

"I firmly believe that the fear we have of dying when we have sex is something we shouldn't have to live with," he said.

"HIV is always in the background. It's almost like you couldn't fully enjoy sex," he said.

Mr Spillane is one of more than 1,100 men across NSW who are participating in Australia's largest clinical trial of the pre-exposure prophylaxis (PrEP) Truvada to protect themselves against HIV and eradicate new HIV infections across the state.

Newly approved on the TGA, the daily pill protects HIV negative men from contracting the infection with an effectiveness rate of 99%, and stems its spread by preventing transmission to partners, potentially cutting the rate of undiagnosed HIV in the community.

"I feel like I'm part of something really important, not only for me personally, but I'm protecting my community. I really strongly feel part of the community and this is a good community," he said.

"It gives me more control over my sexual health and takes away a lot of that anxiety and fear, but it doesn't remove it completely.

It's not often a conservative state MP is called a gay icon without a trace of irony, but that was the moniker given to Jillian Skinner as she championed the the EPIC-NSW trial.

Backed by the minister and run in partnership with UNSW's Kirby Institute and HIV prevention LGBTI organisation ACON, the campaign to secure trial participants hit the staggering milestone of 1,000 participants in three months.

Aiming to recruit 3,700 gay men by the end of 2016, the trial researchers predict the initiative will cut the rate of new HIV infections across the state by 50% year on year and virtually wipe it out by 2020, an ambitious target set by the Health minister in 2012 which has bipartisan support.

"If we can do this I would consider it the greatest achievement of my time as health minister," Ms Skinner said at the official launch of the trial on Friday.

"You have me for life, as long as you keep calling me a gay icon," Ms Skinner told the crowd at the ACON clinic on Oxford Street.

Ms Skinner said gay men had the right to a sex life that was free from the dogged fear of HIV.

"What we're doing is based on science. It's rigorous and it works," she said.

A sustained moral backlash followed PrEP approval in the US, stoked by fears it would lead to rampant promiscuity and an increase in STIs.

In 2012 the term "Truvada whore" went viral.

But Professor Andrew Grulich at UNSW's Kirby Institute said there was little evidence to suggest PrEP use increased the rate of condomless sex and STIs.

"The same sort of thing was said in the 1960s and 70s when a large proportion of women started taking the pill. But did we say 'We shouldn't give women the pill'? Absolutely not," Professor Grulich said.

"Just as women should have the right to control their fertility, gay men should have the right to control the risk of becoming HIV positive," he said.

Within weeks of the trial being announced in December more than 1,500 people had joined the waitlist, as gay men embraced the new prevention method after decades of living with the anxiety of infection.

"We still get comments that gay men are complacent or irresponsible and don't care about HIV, but that's just not true. The response to PrEP shows people in our community are responsible. They want to prevent HIV and protect our community," said ACON director of HIV and Sexual Health Karen Price.

HIV testing and early treatment were still vital, and contraception was essential to protect against other STIs.

Short term side effects of the drug include stomach pains, and trial participants will have quarterly check ups to test for other STIs, as well as monitor bone density and kidney function, which can be affected by the drug long term, but are uncommon, Professor Grulich said.

The next step for advocates was to push for the federal government to subsidise the drug under the PBS when the Pharmaceutical Benefits Advisory Committee meets in July.

"We need this remarkable tool to be funded," Executive Director of the Australian Federation of AIDS Organisations Darryl O'Donnell said.

"Just as the oral contraceptive has transformed the lives of millions of women, PrEP puts the power of HIV prevention in the hands of those who need it," he said.