NEW DELHI, July 26 (Reuters) - India's government confirmed on Thursday that the latest outbreak of bird flu in poultry in the remote northeast of the country was of the H5N1 strain, the first case reported by the country in a year.

Government workers plan to slaughter some 150,000 poultry in a 5 km (3 mile) radius around the affected farm in Manipur state which lies on the border with Myanmar.

Health workers will check for any signs of flu among some thousands of people around the poultry farm in Chingmeirong village on the outskirts of Imphal, the state capital some 1,700 km (1,050 miles) from New Delhi.

Authorities said they are investigating the source of the outbreak after more than 130 birds died. "It has been confirmed as the H5N1 strain," said Joint Secretary in the Minister of Health Vineet Chawdhry.

India declared itself bird flu free last August after two major outbreaks of the H5N1 virus in chickens in western India. It culled around a million birds to contain those outbreaks.

India has had no reported human case of bird flu.

The home ministry has asked border guards to step up watch on the frontiers of the isolated northeast region, connected to the rest of India by a sliver of land.

"It is a difficult border... but we have measures in place which have been further tightened," Upma Chawdhry, Joint Secretary of the Animal Husbandry Department, said.

Imphal is closer to Bangkok and Dhaka than to New Delhi.

None of the people in the poultry unit or veterinary workers dealing with the outbreak are showing flu symptoms, but they have been put on the anti-flu drug Tamiflu as a preventive step.

The confirmation of the H5N1 strain came after authorities received the results from two government laboratories.

NO TO CHICKENS

In Imphal, a town of some 200,000 people, many residents had stopped buying chickens and eggs, important items in the diet of the majority of people in the state.

"Naturally, people are panicky. We are doing our best to contain the outbreak," said Dr. P.J Sharma of the Manipur bird flu control centre.

Authorities have set up a special ward for any suspected human cases of bird flu in a government hospital in Imphal.

Neighbouring Bangladesh, Myanmar and Pakistan have also witnessed outbreaks of the H5N1 strain of bird flu this year in poultry.

New Delhi has banned poultry trade with bird flu-hit nations such as China, Bangladesh and Myanmar but officials are worried about people bringing poultry illegally across the frontiers.

India has close to 500 million chickens of which around 40 percent is backyard poultry. Last year's outbreaks had seen the poultry industry lose millions of dollars as many consumers shunned chicken and eggs.

(Additional reporting to Biswajyoti Das in Guwahati)