China reported eight human cases of the H5N1 strain of bird flu in January, five of whom died, which appeared independent of any known case in birds.
Hans Troedsson, the World Health Organisation's China representative, said their risk assessment had not changed following the new cases as it was normal during the winter months.
"Why we don't expect this is the beginning of an epidemic is these cases are geographically distributed and there are no links between them," he told the Foreign Correspondents Club of China.
"All of them have been exposed either to sick or dead poultry or wet markets. There is plausible explanation for how it can be transmitted. There's no indication of human to human transmission."
One problem is the lack of reports of bird outbreaks.
"What it tells us is we still have a very serious situation in the agriculture sector," he said. "The virus is well-entrenched and circulating in the environment.
"It is of great concern for us. It's something we are raising, both the WHO and FAO, with the government," Troedsson added, refering to the Food and Agricultural Organisation.
With the world's biggest poultry population and hundreds of millions of backyard birds, China is seen as critical in the fight to contain bird flu.
Vincent Martin, the FAO's senior technical adviser in Beijing, said China needed better sampling.
"They are taking millions of samples every year to try to check the status of the poultry population in terms of avian influenza viruses," Martin said. "It's a huge task and it's really a huge challenge for them.
"Although they are doing a lot of surveillance, definitely more can be done. They can increase surveillance, not only increase in terms of taking more samples, but doing it at the right place, doing it where you think you can get the virus."
The H5N1 flu remains largely a virus among birds, but experts fear it could change into a form that is easily transmitted among humans and spark a pandemic that could kill millions worldwide.
The H5N1 avian flu virus has killed 254 people out of 406 infected in 15 countries – Myanmar, Bangladesh, Turkey, Djibouti, Azerbaijan, Egypt, Pakistan, Iraq, Indonesia, Thailand, Vietnam, China, Nigeria, Laos and Cambodia.
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