A spokesperson for the FAO told a conference in Kuala Lumpur, Malaysia, that the ellimination of the virus from the eight affected Asian countries would "not be easily achieved".

"The bird flu virus must be considered as an endemic disease and must be controlled at source in animals," said the spokesman.

The three-day conference which took place over July 4-6 was jointly organized by the FAO, the World Health Organization (WHO) and the World Organization for Animal Health (OIE).

Shigeru Omi, the WHO's regional director for the Western Pacific, warned that the battle against the bird flu virus was at the "tipping point".

Since 2003, the virus has killed 55 people in China, Vietnam, Thailand and Cambodia, most of them after coming into contact with infected birds.

It has also led to the slaughter of over 140 million chickens in an attempt to halt its spread.

The three UN agencies will organise a meeting of international donors this year to persuade western countries to donate at least US$250 million to help bird flu-affected countries over the next three years.

About US$150 million is needed by the WHO for public health programmes including emergency support, vaccine development, anti-viral drugs and public education.

The remaining US$100 million is required by the FAO and OIE for vaccination and surveillance.

"Without international support, poor countries will not be able to battle bird flu," said the spokesperson.