Dr Wooldridge, who is in the United States for the United Nations conference on AIDS, said Australia might continue to go it alone in supporting anti-AIDS efforts in the Asia-Pacific region.

He said Australia contributed $200 million to AIDS programs last year.

But he said it remained unclear how the proposed global war chest to combat AIDS and related diseases would work.

"Yesterday I had lunch with a number of health ministers, people who had been actively involved in the fund that has been proposed, and there is no clear idea of its governance, no clear idea how people are going to draw money out of it, no clear idea of what its focus is going to be," he said.

"So Australia is not able to give a commitment in those circumstances.

"It may be that in the end, if this fund is focused on Africa, we will have to keep giving money bilaterally and multilaterally in our region.

"I think it is unreasonable to expect a country to commit money when it doesn't know what it is committing to."

The UN conference in New York has spent the past four days examining the world AIDS epidemic, which has struck some 36 million people, 25 million of them in Africa.

The disease, first discovered exactly 20 years ago, has killed almost 22 million people and left 13 million children without parents.

Dr Wooldridge said the conference had achieved substantial results although many nations had to make concessions.

"You cannot get 189 nations to come to a common point of view without making concessions," he said.

"The Islamic nations, for example, would feel they have made concessions on women's rights. The western nations have made concession in some areas, such as listing vulnerable groups not going as far as we would have liked to have gone.

"Nonetheless the final document is still an enormous advance on anything we have ever seen before."