The World Health Organization says AIDS is spreading rapidly through China and estimates 10 million people may be infected with the virus by 2010.
The WHO says the disease has spread to all of China's provinces and autonomous regions - with injected drug use the main route of transmission.
It says a similar situation exists in Malaysia and Vietnam.
The warnings came in a statement Tuesday from the organization's regional director, Shigeru Omi. Mr. Omi called for stronger political will by Asian governments to stop the spread of the disease.
Based on the WHO's records for Asia, Cambodia has the highest percentage of people infected with HIV - at 1.9 percent of the population.
Some information for this report provided by AP and Reuters.