Schools remained closed and electricity was down in swathes of the archipelago nation's largest island as the national disaster agency reported 25 dead and eight missing since last Friday.

But those numbers did not account for three construction workers buried in a landslide as they rested Thursday in Cavite province, south of the capital Manila, according to rescuers.

A wall above their construction site collapsed onto the men below after days of rain softened the soil under it, said rescue team member Rosario Jose.

"All the bodies were found in the mud," she said. A lone survivor was pulled from the rubble.

In the west coast province of La Union, where Typhoon Co-May arrived in the early hours, a family of four was rescued Friday morning after being trapped on the second floor of their wooden home.

"They couldn't leave their house because the flood was waist-deep and they have children," said a rescue official who asked not to be named as they were not authorised to speak to media.

"Many had been calling us since early morning, but we were having challenges in responding because the rain and winds were so strong," they said, adding that a break in the downpour meant rescue operations were now in full stride.

In Bulacan province, just north of Manila, AFP journalists saw entire villages half submerged in floodwaters.

Lauro Sabino, 54, said he and his wife had evacuated their home in the morning after a frightening night of hard winds.

"It was as if my roof was being blown off. It was creaking. The rain poured the entire night," he said, adding they would sleep at a local market until flooding subsided.

"The same thing happens every time. There's no solution," agreed Mary Rose Navia, 25, a housewife whose husband was unable to go to work on Friday.

"The floodwaters are just getting deeper."

President Ferdinand Marcos on Thursday explicitly tied the recent flooding to climate change, saying his country had to accept this was the "new normal".

"This is the way it's going to be as far as we know for... many decades to come, so let's just prepare," he said in a televised cabinet briefing.

The storm, which was weakening as it made its way north by northeast, was expected to be gone from the Philippines by Saturday morning.