Torrential rain set off by an approaching storm has swamped eastern Philippine cities and towns in widespread floods that have killed at least nine people, trapped others on their roofs and sparked frantic appeals for help.

Thousands of people were evacuated from their homes as parts of the country experienced unprecedented flooding, the authorities said.

Tropical Storm Trami made landfall in the northeastern portion of the Philippines' main Luzon island early on Thursday, forcing schools and government offices to shut for a second straight day as disaster agencies brace for more rains and floods.