"There is a severe need for the prevention of more cases."
He said health departments needed to pay "great attention" to preventive measures in efforts to control the spread of the H5N1 bird flu virus among humans.
Chinese authorities are bracing for the worst because they say winter and spring are high seasons for infections and that the lunar new year holiday could speed up the spread of the virus.
The holiday is also a peak time of trade for poultry farmers, with duck, chicken and goose traditionally featuring in family new year feasts.
Experts said cold weather was a high season for bird flu virus infections [Reuters]
Despite the recent deaths, China's health ministry said there was no evidence of a large-scale outbreak of bird flu, adding that the new cases were isolated, unrelated and did not show significant mutations of the virus.
Nonetheless health experts said it was important to increase vigilance.
"These cases warn us to improve prevention and supervision over the epidemic and ensure early detection and diagnosis when new cases are found," Shu Yuelong, a flu virus expert at the National Centre for Disease Control and Prevention, was quoted by Xinhua as saying.
The deadly H5N1 strain of flu remains largely a virus among birds but there is fear that it could change into a form that is easily transmitted among humans and could spark a global pandemic.
Bird flu has killed 23 people in China since the disease was first recorded there in 2003.
Worldwide the virus has caused 397 human infections and 250 deaths, with Indonesia recording the highest number of human fatalities.
Until this month, no new human infections had been reported in China since