KUALA LUMPUR (AFP) - Asian countries must remain vigilant against deadly bird flu since it is still rampant in the region, a top UN health agency official said on Tuesday.

"I think countries in this part of the world have done a lot to fight the virus. But in spite of it, the virus is still circulating," said Shigeru Omi, WHO's regional director for the Western Pacific.

"This is the challenge. We remain concerned. We must avoid human transmission," he told reporters at the sidelines of a four-day conference on the impact of climate change and health in Southeast and East Asian countries.

Omi urged authorities in the region to remain alert and prepared even though the H5N1 virus had not advanced to human to human transmission.

"It is important we keep vigilant," he said.

Omi said education and paying of compensation for culled chickens were key in the fight against the virus.

"People must be taught to avoid contact with dying chickens," he said.

Asked about those who transport their fighting cocks illegally across the border between Malaysia and southern Thailand for contests, Omi said: "We need to educate the public (against it)."

Transmission of bird flu to humans remains very rare, and limited to those in frequent contact with infected poultry. But the WHO believes a potential human pandemic cannot be ruled out as long as the virus lingers in birds.

Indonesia remains high-risk because of the permanent contact that many people in the country have with domesticated birds. It has been the worst hit nation by the deadly H5N1 virus, with 80 fatalities to date.

In Indonesia alone, the WHO estimates that there are more than 13,000 poultry markets, where birds from many different places are exposed to each other, raising the danger of transmission.

Since 2003, the H5N1 virus has infected 310 people, including 190 who later died, according to WHO figures. Some 250 million poultry have also been culled, or have died from bird flu.