AIDS experts are hoping a global conference in Vancouver will lead to changes in the way the world treats HIV.

AIDS researchers have called for a worldwide shift in HIV treatment, saying medication should be provided immediately after diagnosis rather than waiting for signs of illness to appear.

"Immediate antiretroviral (ARV) treatment more than doubles an individual's prospects of staying healthy and surviving," said the Vancouver Consensus, a statement signed by leading scientists and officials at the International AIDS Society conference in Vancouver.

They said new research would be presented to the conference which showed immediate treatment prevents infected people from passing on the infection.

Meanwhile, other reports will show that preventive therapy "can effectively protect people at risk of infection through prophylactic use".

The last global AIDS meeting in Vancouver, in 1996, marked a breakthrough - with research showing that triple-combination antiretroviral treatment worked.

The findings meant that instead of an HIV diagnosis being an almost-certain death sentence, it became possible for an infected person to live a normal life while on treatment.

"Vancouver is going to make history again," said conference co-chair and researcher Julio Montaner.

"Because prevention will be definitely established at this conference as the new standard of care."

Other research will show it is possible to decrease HIV transmission rates by 95 per cent.

"We now have the opportunity of ending the pandemic," said Montaner, challenging politicians to support treatment.

"Leaders of the world, you're either with us or against us. We know the evidence. It's up to you as to whether you will be counted as doing the right thing."

He read out a letter to the conference from the Vatican promoting treatment and prevention.

"If the Pope gets it, everybody else should," Montaner told a news conference prior to the conference opening on Sunday night.