A Vietnamese farmer uses a stick to slaughter chickens (AFP)

Thai Premier Thaksin Shinawatra, whose government has faced accusations that it covered up the disease before finally admitting January 23 it had a massive outbreak, said his country had not been remiss in handling the crisis.

"The bird flu outbreak was a new experience for Thailand, so it's usual for Thailand to grope for its way before we find a clear answer," government spokesman Jakrapob Penkair quoted Thaksin as saying in a television interview, reported Agence France-Presse (AFP).

With 10 Asian countries reeling from the lightning spread of avian flu and eight from the virus' highly pathogenic H5N1 strain, experts meeting in Rome slammed the region's response to the crisis that has killed at least 18 people.

"The epidemic has not been brought under control and we need an urgent response," FAO director Jacques Diouf said Thursday, adding that the disease must be prevented from spreading geographically and to other animal species.

"I can say that all countries were much too slow on reporting", Vallat said Thursday following a two-day meeting of international animal health experts on the bird flu outbreak in Asia.

"All countries could have notified more quickly", said Vallat.

Vietnam has suffered the largest number of human fatalities from the disease, with 13 deaths out of 17 confirmed infections.

The government says bird flu only broke out in late December.

"It is not the policy of the Vietnamese government to cover-up information," Le Dung told reporters.

The international experts in Rome said targeted vaccination would help prevent animals falling ill and reduce the "viral load", or the amount of virus present in the environment.

Reducing the viral load will draw down the potential for avian influenza spreading to humans, the experts said.

But Thai deputy Agriculture Minister Newin Chidchob rejected the call for a poultry vaccination program and insisted Thailand would continue with its culling procedures that have seen millions of chickens slaughtered.

"No vaccine, Thailand will use only elimination, and we have no vaccine," he told AFP.

Thailand has confirmed five people have died from bird flu, with 20 more suspected human cases, nine of which were fatal.

A chicken with the bird flu virus tries to escape from a bonfire of burning chickens in Indonesia

In South Korea, which in mid-December became the first Asian nation to report an outbreak in the current epidemic, the government dodged the criticism as it immediately set up a task force to fight the disease and keep the public informed of quarantine measures within the country.

It also hedged its bets on the call for a vaccine program, saying it still regarded the culling of poultry as the most effective tool to fight the disease.

Japan, however, said it was considering stockpiling poultry vaccines in case of a further outbreak there, but stopped short of announcing a vaccination program.

"A government panel of experts has told us to consider stockpiling vaccines just in case the virus spreads" beyond one farm in southwestern Japan, said the official who is in charge of safe consumption of farm products.

"We have started to make the necessary arrangements to do that," the official said. "Fortunately, we have the outbreak under control, and we don't see the immediate need for a poultry vaccination campaign in Japan."

The island nation, where a bird flu outbreak was reported in just one farm, rejected allegations of being too slow to report it, the official said.

"We believe we have been promptly reporting information related to the outbreak," he said. "If the criticism is targeted at other nations, we hope they will react responsibly and take appropriate measures," he said.