Canadian researchers have spent 10 years developing an HIV vaccine for human testing -- and now have approval to begin clinical trials.

The U.S Food and Drug Administration has given researchers at the University of Western Ontario the go-ahead to test their vaccine - which they call an extremely significant milestone.

Starting next month, the clinical trial will test the safety of the vaccine in 40 HIV positive volunteers, who will be tracked for about three years.

If the SAV001 vaccine is found to be safe, it would require two more clinical trials that prove it works before it could be brought to market.

The final phase of testing would require about 6,000 high-risk subjects, half of whom would be vaccinated and half unvaccinated.