Hundreds of soldiers were ordered to carry relief supplies on foot to three devastated towns on the eastern coast after roads were cut off and bad weather grounded rescue helicopters on Wednesday.
"We need to bring food, medicine and blankets to affected communities today because another typhoon will hit these areas and it could be more difficult to reach thousands of families waiting for these relief goods," Major-General Pedro Cabuay Cabuay told local radio.
Officials said residents were appealing for body bags and lime for hundreds of corpses that were starting to decompose.
In the town of Real, rescuers used sticks and bare hands to search for friends and relatives who had taken shelter in a large building that then collapsed.
Neri Amparo, an official at the National Disaster Coordinating Centre, said more than 70 people could have been buried alive when boulders swept by mudslides smashed into the building.
"So far, only 25 bodies have been found," she said.
Past landslides have been blamed
on soil erosion caused by logging
At least 306 people died in the towns of Real, Infanta and General Nakar in Quezon province, about 80km east of capital Manila, after heavy rains caused flash floods and landslides, Social Welfare Secretary Corazon Soliman said on Tuesday.
She said 150 people were missing in Real alone. Officials said 43 people had been confirmed dead in other areas.
Witnesses said flimsy houses in the three towns were swept away on Monday night by a torrent of timbre and mud, possibly loosened by years of illegal logging.
President Gloria Macapagal Arroyo, who returned early from a Southeast Asian summit in Laos, to help coordinate rescue efforts, said she had ordered a nationwide crackdown on illegal logging, blamed for several recent landslide disasters.
"Illegal logging must now be placed in the most serious crimes against our people," she said on Wednesday.
President Arroyo: Illegal logging
must be seen as a serious crime
Floods and landslides that killed more than 200 in Southern Leyte province a year ago were also blamed on soil erosion caused by logging.
Meteorological officials said Typhoon Nanmadol, packing winds of 160kph at its centre, was gaining strength and was expected to hit the east coast late on Thursday or on Friday.
"We are hoping that the typhoon would change course," said Rose Asejo, an official at the national weather bureau. "We haven't seen anything like this since the start of the year. It's a super typhoon with a wider coverage and very strong winds."
The weather was already worsening.
Attempts to reach the towns with the country's few rescue helicopters failed, and a navy ship ferrying relief supplies to Real was stuck there due to high waves and logs in the sea.
Soldiers helping in rescue efforts faced the added danger of attacks by communist rebels, who have a strong presence in the Sierra Madre mountains along the eastern coastline.
The military said 10 soldiers were killed and six wounded in an ambush by New People's Army rebels in Bulacan province on Tuesday.
"My body was getting numb ... I was ready to give up"
Survivor Dante Runes
Some flood victims had lucky escapes.
One 20-year-old man and his heavily pregnant wife were swept along in a flooded river for two hours, surviving by clinging to a water jug and a banana crate before being fished out by a local resident, the Philippine Daily Inquirer reported.
"My body was getting numb ... I was ready to give up," the newspaper quoted the man, Dante Runes, as saying.
The Philippines is hit by about 20 typhoons every year. The most destructive in recent times was Thelma, which struck Leyte island in November 1991 and unleashed floods in Ormoc City that drowned about 5000 people.