MANILA : Government experts are closely monitoring migratory birds in wetlands across the bird flu-free Philippines for signs of the virus, a senior official said Tuesday.

Environment and Natural Resources Secretary Angelo Reyes urged the public to help government monitors by looking out for multiple deaths among both domestic poultry and migratory waterbirds.

"The Philippines is still bird flu-free, but the threat of the virus is ever present," Reyes said in a statement.

"There is an upsurge in bird flu cases in Asia, Europe and Africa and we hear reports of new cases in several countries. We do not want that to happen here."

The countries reporting new cases include Indonesia, Thailand, Vietnam, South Korea, Japan, Egypt, Nigeria, Hungary and Russia.

The government agency "has instituted measures to minimise the probability of entry of the deadly virus. We can take precautionary measures by taking surveillance of areas where migratory birds congregate," he said.

The monitors recovered a "very sick" heron at a wetland feeding area near Prieto Diaz town on the southeastern tip of the main island of Luzon, the department said.

The results of the tests on the bird have not been published.

Surveillance at airports and seaports was also stepped up to stop the smuggling of wild birds and poultry, Reyes said.

The agriculture department has meanwhile banned poultry imports from areas hit by avian influenza, most recently Japan.

Some 270 cases of humans being infected by the bird flu virus had been reported worldwide since 2003 with 164 deaths as of last month.

More than 200 million chickens, geese, ducks and other poultry have been culled over the past years in an effort to stop the spread of bird flu in these areas. - AFP/ch