China's Health Ministry had informed the World Health Organisation of the outbreak in the southern region of Guangxi shortly after its confirmation as the same strain that has killed eight people in Vietnam and Thailand.
Dr Julie Hall, a WHO coordinator in Beijing said on Tuesday the government was taking the latest outbreak very seriously and appeared to have learned from its fight against the deadly SARS virus last year.
"They reassured us that at this moment in time that there have been no human cases of avian influenza," Hall said.
"But clearly it is of concern now that there is an outbreak here in China. The opportunity to interact with human beings is obviously very apparent," Hall said in an interview.
China's huge population and humans living in close proximity close to poultry, pigs and other livestock in farms across the country's southern regions alarm epidemiologists, who worry they will be cauldrons for the next big flu epidemic.
Hall said at this point, it was "very difficult" for the H5N1 virus to spread between animals and humans, apparently requiring close contact with a live, sick animal.
"But the more opportunity it has to go back, the more opportunity it has to transmit more easily between animals and humans," Hall said.
"It is very urgent that the matter is dealt with quickly," Hall said.
Culls and quarantine of poultry should be implemented and human contact with animals limited in order to prevent the opportunity for the virus to transmit to humans, she said.
WHO also wanted regular contact with the Ministry of Agriculture, which confirmed the outbreak.
Some health experts fear the bird flu virus could spark an epidemic worse than SARS, another disease that crossed from animals to humans last year, killing 800 people around the world.
Experts fear bird flu virus could
spark epidemic worse than SARS
China, after initially covering up that outbreak, mobilised the country, declaring war on the disease and setting up health checks and quarantine measures to eventually defeat it.
"China obviously has large numbers of animals, large numbers of people, but we know from SARS there are some systems in place to detect an outbreak quickly," she said.
"We know the government is taking this issue seriously," she said.