HANOI (AFP) - Health officials in Vietnam on Friday confirmed a farmer has been infected with the deadly bird flu virus, the first human case in the country since late 2005.

"Two recent tests for the 30-year-old man from Vinh Phuc province showed that he was positive to the H5N1 virus," said a doctor from the National Institute of Epidemiology in Hanoi who refused to be named.

State-run Vietnam News Agency also quoted deputy head of the ministry´s Preventive Healthcare department Nguyen Van Binh confirming the test results.

The ministry of health has not directly confirmed the case and the World Health Organisation (WHO) said it was still waiting for confirmation from its own laboratory tests.

The man, who is in critical condition in a Hanoi hospital, helped slaughter chickens for a wedding about a month ago from a neighbouring farm, where several birds later died.

This is the first human infection since November 2005 in Vietnam, which was one of the countries hardest hit by the virus with 42 human fatalities between 2003 and November 2005.

The virus has remained endemic to wild and domestic bird populations, and struck again this month with several outbreaks of the H5N1 strain in eight provinces killing thousands of unvaccinated ducks and some chickens.

Vietnam says it has vaccinated more than 120 million poultry in 60 provinces in efforts to combat the virus.

The News newspaper quoted Prime Minister Nguyen Tan Dung as criticising on Thursday local authorities for their lack of responsibility in monitoring the situation.

He also urged them to apply all possible measures to prevent the spread of the epidemic to both poultry and humans.

The WHO representative in Vietnam, Hans Troedsson, said the new developments were not "surprising."

The virus "was pushed back by the measures Vietnam has taken, with the mass vaccinations and cullings," he said, but it "has never been eradicated."

However, the Vietnamese authorities "are doing the right things," he said, adding the situation was "not alarming."

According to World Health Organisations figures, the H5N1 strain of bird flu has infected at least 306 people worldwide and killed about 185 of them, mostly in southeast Asia.