Another typhoon is set to hit the Philippines, which is already reeling under the impact of two back-to-back storms.

More than 500 people died in the previous storms, and the latest one, Typhoon Nanmadol, packing winds of up to 200 km/h, is expected to make landfall on the east coast of the Philippines islands in the next 48 hours.

At least 350 people died and 150 went missing after a storm triggered landslides and flash floods on the east coast two days ago.

Another one last week had left at least 90 dead and scores missing.

Rescuers are battling difficult conditions in the hunt for the missing people.

The worst-hit coastal towns of Real, Infanta and General Nakar remain cut off by floodwaters and smashed bridges. According to reports, several thousand people are stranded on rooftops in the three towns.

Helicopter crews are struggling to find ground solid enough to land on and are dropping food packages on the rooftops.

President Gloria Macapagal Arroyo will return early from a regional summit in Laos to visit the storm-ravaged areas on Wednesday.