The warning came ahead of a meeting in the western Japanese city of Kobe of 3,000 health care experts and HIV/Aids activists from around 60 countries.

"This conference is taking place at a very critical moment for the region when it comes to Aids," said Peter Piot, executive director of UNAIDS.

"The risk of HIV spreading throughout the region is higher than ever, despite some progress in several countries," he told reporters, stressing that only "scaled up responses" by governments can change the trend.

Worldwide, about 40 million people are infected with HIV, the virus which causes Aids, of whom about 8.2 million, or roughly 20 percent, live in Asia, according to UNAIDS. Of the 8.2 million, 1.2 million were infected in 2004 alone.

World leaders and the public must realise that the fight against HIV is as important as global security, Piot said.

"If business as usual continues over the next five years, at least 12 million people will become infected with HIV.

"If we work hard and if we are going to face the realities ... new infections can be prevented, at least six million," he said.

Organisers said the Seventh International Congress on Aids in Asia and the Pacific, which begins later Friday and runs until Tuesday, will focus on a wide range of issues, including the latest treatment and prevention measures.

The conference provides "a space for everybody involved in the fight against HIV/Aids to be together," said Dennis Altman, president of the Aids Society of Asia and the Pacific.

"There is a free arena in which people living with Aids from marginal, vulnerable communities to come face to face with government and international officials," he said.

The Kobe event, which follows the sixth congress in Melbourne, Australia in 2001, was originally scheduled for 2003 but was postponed due to the outbreak of Severe Acute Respiratory Syndrome in Asia at the time.

The regional fight against HIV has been made difficult due to public stigma against the disease and lack of understanding among policymakers, Piot said.

Countries such as Thailand and Cambodia have successfully implemented prevention programmes to push down the level of new HIV infections, while others, such as Indonesia and China, have seen soaring rates of infection.

The cultural diversity of Asia and the Pacific calls for flexible approaches to tackle HIV, experts said.

They also pointed to the sharp rise in the movement of people triggered by globalisation and robust economic growth in China and India, the world most populous countries, that have made it easier for the virus to spread.

"The countries are taking proactive steps but we are concerned that the pace of their responses and the pace of global responses have not matched the pace of the epidemic itself," said Jack Chow, the World Health Organisation's assistant director-general of HIV/Aids, tuberculosis and malaria.

"We want to create a force of change that surpasses the rate of epidemic," he told AFP.