The World Health Organization (WHO) warns that drug use, unsafe paid sex and unsafe sex between men are driving the spread of new infections in Asia.
Over 8.6 million people in Asia have HIV - nearly one-million of them were infected in the past year.
Of the 650,000 people with HIV in China, drug use accounts for nearly half of those infections. The Chinese government says the number of HIV infections jumped 30-percent from January to October this year, compared with a year ago.
WHO says half of those infected this year in China contracted HIV through unprotected sex. It says many male drug users in China buy sex and as many as half of female drug users sell sex. Experts say the trend reflects the low level of public awareness about HIV in Asia, partly because sex is often treated as a taboo subject and also because governments had been slow to respond to the crisis.
In recent years, top Chinese officials have visited AIDS hospitals to increase awareness. But Dr. Joel Rehnstrom, head of the U.N. Program on HIV/AIDS office in Beijing, says more needs to be done.
"Despite an increased openness and willingness to talk about AIDS, also increased reporting on AIDS in Chinese media and increased awareness campaign, we still see among young people, students, among the general population many misconceptions, lack of understanding of how HIV is spread or how to protect yourself," he said.
The Chinese government sometimes arrests activists for doing AIDS awareness work outside state sponsored programs.
Experts also worry about the spread of AIDS in isolated Burma, where awareness and prevention programs are weak, and in Vietnam, where the number of people with HIV has doubled since 2000.
In Indonesia, the most populous Southeast Asian nation, Health Minister Siti Fadilah Supari has warned that HIV cases could rise to half a million people in four years from about 200,000 today. She says only 15-percent of those who hire sex workers in Indonesia use condoms.
As the infection spreads, governments and private organizations struggle to deliver affordable treatment. Only one-in-six people with HIV in Asia receives anti-retroviral drugs, which slow the progress of the virus and prolong the lives of those infected.
The Chinese, Indian and Thai governments provide free anti-retroviral drugs. But so far in China, only 25-percent of those in need of drugs have access to them.
In India, where two-thirds of Asia's HIV/AIDS infected people live (5.7 million), only 10-percent have access to treatment. More than half of the people in India with HIV live in impoverished rural areas. Activists say they cannot afford to travel to the cities where most free clinics are.
Women, in particular, are missing out, says P. Kousalya, president of the Positive Women Network, a private organization in the southern city of Chennai that helps women with HIV. She says many women with HIV in India contracted the disease from their husbands, who have since died, leaving their wives to support their families.
"Women are not able to travel in the city. They have to spend a lot of money for the traveling," she said. "And they are not able to go to work so they would lose one day salary."
Experts say there are encouraging successes in curbing the spread of AIDS in Asia.
Although it remains an AIDS hot spot, the prevalence of HIV among adults in Cambodia is now one-third lower than in 1990s - a product of prevention efforts especially targeting unprotected sex. And in Thailand, where the prevention campaign had been aggressive, new HIV infections have been declining since the 1990s.