President Benigno Aquino warned that Typhoon Koppu - which is due to hit early on Sunday - could bring up to 12 hours of torrential rain.
Local authorities have been urged to evacuate residents in flood-prone areas along the country's north-eastern coast.
The Philippines is still reeling from Super Typhoon Haiyan, which killed more than 6,300 people in November 2013.
Haiyan, the strongest storm ever recorded on land, destroyed entire towns.
Typhoon Koppu has produced winds of up to 180km/h (115mph) and is slow moving, meaning it could bring intense rain over a long period of time. The wind could be strong enough to blow down trees, rip roofs off buildings and threaten power supplies.
The first heavy rain was expected in parts of the northern island of Luzon on Saturday.