There is little likelihood that bird flu will break out massively in China this year, thanks to the country's intensified vaccination efforts, Chief Veterinary Officer Jia Youling said yesterday.

But as vaccines might be improperly administered in courtyard farms in some remote areas, and as migratory birds fly north to their summer nesting grounds, avian influenza is still a threat, said Jia, also chief of the Veterinary Bureau under the Ministry of Agriculture.

"By last Wednesday, 4.75 billion vaccines had been used throughout the country, and poultry in most regions are expected to have been vaccinated by the end of this month," he told reporters.

Talking about the country's expertise in fighting bird flu, Jia said a combination of culling and vaccination held the key to current achievements.

Last week, when United Nations co-ordinator for avian influenza David Nabarro visited China to take stock of what the country has done, he called for China to contribute its expertise and information to the global bird flu fight.

China had undertaken the world's biggest vaccination campaign and slaughtered 22.849 million poultry since 2005, according to ministry sources.

As a result, it has stamped out all 35 outbreaks of the deadly H5N1 virus since last year, and has not reported a single new bird flu case in the past one and half months, Jia said.

The ministry has been active in co-operating with international organizations for the control of bird flu, and has invited at least 30 experts from the World Health Organization and the UN Food and Agricultural Organization to visit epidemic sites and laboratories in China, he said.