Tropical storm Mitag bore down on the eastern Philippines on Wednesday, flooding large areas of the region and forcing the government to order large-scale evacuations, days after another killed 10 people in the country's south.

Mitag was gaining strength with winds of up to 85 kilometres (53 miles) an hour and was on course to hit the Bicol peninsula southeast of Manila on Friday, weather forecasters said.

It was tracked 1,020 kilometres northeast of Legaspi, Bicol's largest city, at 11:00am (0300 GMT), and forecast to reach typhoon strength of at least 120 kilometres an hour when its eye passes close to the island of Catanduanes, to Legaspi's northeast.

At least 200,000 people needed to be evacuated, Anthony Golez, deputy civil defence chief, said.

President Gloria Arroyo would cut short by one day her visit to Singapore, where she was attending an Association of Southeast Asian Nations summit, and fly back to the Philippines later Wednesday, aides said.

She wants to "bring people out of harm's way," and has ordered an evacuation of Bicol residents potentially at risk from the storm, Golez told reporters.

"This disturbance is expected to cause flooding, flash floods, landslides and storm surges within the next 24-36 hours," the civil defence office said in a statement.

It called for "preventive evacuation of those in low-lying areas, stockpiling of emergency relief supplies and putting on alert status all response units." The government agency said flooding had already displaced about 2,000 people in three Bicol towns.

Tropical storm Hagibis blew out into the South China Sea on Tuesday after killing 10 people and displacing about 30,000 others in southern and central islands.