Drug companies may not be able to produce enough bird flu vaccine in time to combat a human pandemic, a top UN official warned yesterday as governments scrambled to contain the deadly virus.

It could take six months to manufacture adequate vaccine stocks, and current stockpiles may be useless because the flu virus has mutated, said David Nabarro, UN co-ordinator for global readiness against an outbreak.

He said "very high priority" efforts were underway to raise manufacturing capacity so that a vaccine could be produced more quickly once a virus emerged that could cause a pandemic.

He said current stockpiling by governments around the world may prove useless since they are preparing for an unknown mutation of the virus.

Hungary, meanwhile, said it will know within a fortnight whether human trials of a vaccine have been successful, opening the way to mass production. Health Minister Jeno Racz said if the results were positive, up to half a million doses could be produced weekly within three months.

Turkey yesterday slaughtered more fowl to combat an outbreak amid warnings that the killer virus could spread. The cull continued also in Romania.

Louise Fresco of the UN Food and Agriculture Organisation said that the flu in Turkey could be due to the particularly dangerous H5N1 virus which has caused more than 60 human deaths in Asia. But she said definitive results of tests were still awaited.

After the preliminary Turkey findings, Lebanon, Syria and Jordan said they would take precautions. Egypt's health ministry put in place contingency measures to prevent an outbreak, the MENA news agency reported.

Poland earmarked 420 million zlotys (BD49m) to fight an eventual outbreak and said it will order its poultry kept inside pens if Romanian cases of avian flu turned out to be caused by the H5N1 strain.

PHOTO CAPTION

Ducks for sale at a market in Phnom Penh. (AFP)