A drug which can reduce the risk of HIV infection will be trialled in South Australia, the State Government has announced.

The drug called PrEP — short for pre-exposure prophylaxis — will be available to eligible South Australians who do not have HIV and who are at high risk of acquiring the virus.

The Government said it would begin talks with other states who are leading PrEP access trials and said modelling indicated about 500 South Australians may be eligible to be part of the trial.

Participants would be prescribed a daily oral pill.

Over the past five years, there has been an average of 58 HIV infections notified in South Australia each year.

Premier Jay Weatherill said it was an important new trial for HIV prevention medication.

"The State Government is committed to providing the best possible health care for South Australians and our impending trial of this valuable medication is another example of this," Mr Weatherill said.

Last week Greens MP Tammy Franks said the pill had been shown to reduce infection rates overseas and South Australia was lagging behind by not conducting its own trials.

Trials are already being conducted in New South Wales, Victoria, ACT and Queensland, she said.

An application to list the drug on the Pharmaceutical Benefits Scheme (PBS) was not approved in August.