SYDNEY, Australia (AP) -- International agencies have been slow to promote circumcision as a means to prevent millions of new HIV infections a year because -- unlike a new drug -- almost no one stands to make money from the treatment, a top health official said Tuesday.

The World Health Organization says male circumcision reduces the risk of female-to-male transmission of the disease by around 60 percent. But only 30 percent of men worldwide have had the procedure, mostly in countries where it is common for religious or health reasons.

Robert Bailey, a professor of epidemiology at the University of Illinois, said uncircumcised men are 2-1/2 times more likely to contract the virus from female partners, based on random control trials conducted in parts of Africa hardest-hit by the epidemic.

But international agencies have been slow to implement the procedure despite mounting evidence of its efficacy in preventing new HIV infections, Bailey told a major international AIDS conference in Sydney, Australia.

"One cannot help but contemplate that if it were a drug or a compound or a shot with a label, international agencies and donors would have been fighting to be the first to make it available many months, even years, ago," he said.

"But no one stands to profit from male circumcision -- no one but the 4,000 in Africa who will be infected tomorrow," added Bailey, who has conducted circumcision-related studies in Uganda, Kenya, Malawi, Zambia and the United States.

Studies suggest that widespread male circumcision in sub-Saharan Africa could prevent 5.7 million new cases of the disease and 3 million deaths over 20 years.

If just 50 percent of men underwent the procedure in parts of South Africa, which has one of the world's highest rates of HIV/AIDS infection, incidents of the disease among heterosexual men could by reduced by up to 9 percent over 10 years, Bailey said.

"In other words, circumcision could drive the epidemic to a declining state toward extinction," Bailey said. "We must make safe, affordable, voluntary circumcision available now."

The World Health Organization issued a statement in March urging heterosexual men to undergo the procedure because of compelling evidence that it reduces their risk of getting the disease.

However, it cautioned that male circumcision is not a complete protection against HIV, and said men should still use condoms and take other precautions such as abstinence, delaying the start of sexual activity and reducing the number of sexual partners.