CLARK, PHILIPPINES - The Philippines has begun evacuating thousands of people, local officials said Sunday, as a powerful typhoon rumbling in from the Pacific forced Southeast Asian Games organizers to cancel or reschedule some events.

Forecasters expect Typhoon Kammuri to make landfall Monday evening or Tuesday morning, packing gusts of 170 kilometers per hour and maximum sustained winds of 140 kph.

The storm entered Philippine territory Saturday evening, shortly before President Rodrigo Duterte and boxing superstar Manny Pacquiao launched the Games with a colorful opening ceremony.

This year's Games in Clark, Manila and Subic, which run through to December 11, are already particularly complex with a record 56 sports across dozens of venues that are in some cases hours apart by car.

Outdoor events in Subic -- on the west coast of the main Philippine island of Luzon in the country's north -- were the first to be affected by Kammuri.

"The windsurfing has been cancelled until we have a more accurate picture of the weather," Ramon Agregado, the organizing committee's head of the Subic cluster of venues, told AFP.

The women's triathlon event was brought forward to Sunday, Agregado said, "so we could take advantage of the good weather".

Duathlon events scheduled for Tuesday will now take place on Monday.

Agregado said that venues will not be changed, but in the event of bad weather the equipment will be taken down and put back together once the events are rescheduled.

Some local government units in central Bicol region urged people to begin leaving their homes on Saturday night.

By Sunday afternoon, more than 3,000 people were in evacuation centers, mostly in schools and gymnasiums in Camarines Norte, the disaster management office of the province said.

Most of them live in coastal areas and low-lying places where flash floods and landslides are possible due to heavy rains that will be brought by the typhoon.

No mandatory evacuation has been ordered yet, the disaster management office said.

School classes and government offices in some towns will be closed Monday and Tuesday in anticipation of the heavy rains. -AFP