Vietnam has culled more than 2,500 chickens from a farm in the Mekong Delta area in an effort to contain a bird flu outbreak, officials said Thursday, amid heightened fears about the virus in the region.

Tests were carried out after several of the animals were found dead at a poultry farm in the district of Binh Phu, southern Vietnam, said Thai Quoc Hieu, deputy director of animal health in Tien Giang province.

"Over 2,500 chickens have been slaughtered after testing positive for the H5N1 virus on Monday," he told AFP.

Vietnam has recorded one of the highest number of human deaths from bird flu in southeast Asia, with 59 fatalities since 2003, according to the World Health Organisation, although the last human death was in April 2010.

Last week, China reported its first human fatality from the disease in 18 months, prompting renewed concern about the virus.

"We examined the health of all people living in a radius of three kilometres (1.8 miles) around the farm," Hieu said, adding that there had been no sign of the virus among the local population.

He said bird flu tends to reappear when the weather begins to cool in the region.

Another 450 chickens were culled in the southern province of Hau Giang last weekend after they too tested positive for the H5N1 strain of the virus, a local veterinary official told AFP.