The Philippines started monitoring suspected bird flu cases in humans today after 34 farm workers in two towns north of the capital Manila developed flu-like symptoms after direct exposure to infected fowl.

Officials from the Departments of Health and Agriculture said laboratory tests in Australia confirmed an outbreak of the deadly H5N6 strain of the bird flu virus. The strain is transmissible to humans, but the mortality rate is low.

The Philippines has culled more than 470,000 chickens, ducks and quails in three towns

Health Minister Paulyn Ubial told a news conference the 34 suspected cases of bird flu infection in humans were detected in provinces of Pampanga and Nueva Ecija, on the main Philippine island of Luzon, north of the capital Manila.

"They developed fever, cough and cold," she said, adding some of them had diarrhoea.

"All of them had direct exposure to fowls and they developed common symptoms of influenza. They were already given medicines but we are now monitoring their conditions."

The Philippines has culled more than 470,000 chickens, ducks and quails in three towns in Pampanga and Nueva Ecija since Aug. 11, a day after government confirmed the first bird flu outbreak in the country.

Nearly 500 soldiers have been mobilised to speed up the culling of infected fowl in about 40 farms in the town of San Luis in Pampanga and in San Isidro and Jaen in Nueva Ecija.

The Philippines joins countries in Asia, Europe and Africa that have had bird flu outbreaks in recent months. Many strains only infect birds, but the H7N9 strain has led to human cases, including deaths, in China.