One in four new infections occurs in Asia, home to more than half the world's people, and 1,500 die in the region each day. The disease has spread to all provinces in China, while the number of Indian HIV/AIDS patients are second only to South Africa.
Tonette Lopez, a 30-year-old who worked in bars in her native Philippines for three years and has founded an NGO for sex workers, accused major international agencies of being out of touch with the very communities they were trying to reach.
"Sometimes because they are the funders, they think they know what's best for us, when in fact it should be the other way around," she said on the sidelines of an international AIDS conference in the western Japanese city of Kobe.
"We're the ones in contact with the community, not them," she added. "They're only in their offices, sitting down and waiting for their reports. And sometimes reports are not true," she said.
Though she acknowledged that agencies can provide a badly needed structure for prevention efforts, she urged them to make more of an effort to include the sex workers, who as peers are able to reach out to their communities most effectively.
"There should be greater participation from us -- and they should put us first," she said.
The UN estimates 8.2 million people are infected with the human immunodeficiency virus (HIV) in Asia, about 5.1 million of them in India. The Chinese government says there are 840,000 patients in China.
Worldwide, about 39 million people have HIV/AIDS, including 25 million in sub-Saharan Africa.
Commercial sex is one of the main forces behind the spread of HIV in many countries in Asia, where the United Nations says that 12 million people could be newly infected in the next five years if prevention programmes are not intensified.
Though the infection rates of AIDS are highest among injecting drug users in Asia, the huge numbers of people involved in buying and selling sex makes it a critical concern.
"How we deal with the sex trade will have a decisive effect on HIV epidemics in Asia and the Pacific," Cheryl Overs, an activist with International HIV/AIDS Alliance, told a session of the conference, which lasts until July 5. "The effort must be massive in scale and as diverse as the region itself," he added.
Prevention efforts face new challenges, however, as the sex industry changes in response to modernisation.
The spread of karaoke bars, where sex workers can often make more money than in brothels, and widening use of mobile phones that mean sex workers no longer congregate in specific "red light" areas, make it harder to target specific prevention programmes to the people who need them most.
While women still make up the overwhelming number of sex workers, there is also a need to reach other groups, such as men who sell sex to other men, and transgenders such as Tonette, who tend to be ignored altogether.
The conference is stressing the importance of condoms, whose use varies widely according to the nation and the situation.
One survey conducted last year in East Timor, Asia's newest nation, found that four out of 10 sex workers did not recognise a condom when shown one.
Even when condoms are available and their effectiveness known, decisions on using them can be highly arbitrary. Young men in Laos often base their choice on the woman's body temperature and whether she seems 'promiscuous,' researcher Soutchay Pheualavong said.
Thailand and Cambodia have had noted successes with education and condom outreach programmes among sex workers and other vulnerable communities. In Thailand, annual new HIV infections fell from nearly 143,000 in 1991 to 21,260 at the end of 2003.
For the greatest success, such outreach programmes should involve other sex workers, Tonette said.
"You have the experience, you know how it is, you know how it feels -- and you can get through the message to everyone," she added.