China’s agriculture ministry has called for stepped up efforts across the country to immunise poultry and help stave off bird flu, a new outbreak of which has killed nine people in Vietnam in recent weeks.

The latest outbreak of the deadly disease posed a “large threat” to China, the ministry said in a statement posted on its Web site, http://www.agri.gov.cn, on Tuesday.

China has not detected any cases of bird flu since an outbreak in July 2004 in the eastern province of Anhui, but agriculture officials have said the disease posed a risk during the autumn and winter migration season.

Agriculture Minister Du Qinglin said at a meeting on Monday that the ministry was requiring all local governments to strengthen efforts to vaccinating poultry, especially on large farms in key areas, aiming for 100 percent of the farm bird population.

Du also urged local governments to improve the supervision of markets and transportation of live poultry to prevent the H5N1 virus from entering China, the Web site reported.

He also asked authorities to educate farmers in how to prevent bird flu.

Avian influenza has spread across more than a third of Vietnam and killed nine people in the past three weeks.

Agriculture Ministry officials have denied rumours that there were outbreaks of bird flu in the provinces of Yunnan and Guangdong.

The region of Guangxi, which borders Vietnam, has sealed off all border trade with Vietnam, the official Xinhua news agency on Tuesday quoted local officials as saying.

Last week, the World Health Organisation warned that the bird flu virus was endemic in Asia and appeared to be evolving in ways that could lead to a human outbreak.