A powerful typhoon has brought heavy rains and strong winds to eastern Philippines, toppling trees, overturning tin roofs and cutting power lines in areas still bearing the scars of a super typhoon 13 months ago.

Hagupit - Filipino for "smash" - moved in from the Pacific Ocean and made landfall over remote fishing communities of Samar island on Saturday night, with wind speeds of up to 210km an hour, according to PAGASA, a local weather agency.

Hagupit had weakened to a Category 3 storm, two notches below "super typhoon", but could still cause huge destruction with heavy rain and storm surges of up to 4.5 metres, PAGASA said.

Al Jazeera meteorologist Everton Fox said much of the Philippines could expect heavy rain.

Hagupit was moving "very, very slowly", and could remain in the typhoon-prone country for two to three days, he said.

Reuters news agency reported that about one million people had already fled to shelters by the time Hagupit made landfall, in what a UN agency said was one of the world's biggest peacetime evacuations.

Coastal areas evacuated

People left coastal villages and landslide-prone areas in Samar and Leyte provinces, areas devastated from last year's super typhoon Haiyan, which killed more than 7,300 people.

The wind strength made Hagupit the most powerful storm to hit the Philippines this year, exceeding a typhoon in July that killed more than 100 people.

At least 47 of the country's 81 provinces are potentially at high risk, with weather officials still unclear over its forecasted path. There is no reported casualties yet.

The UN Office for Disaster Risk Reduction (UNISDR) said about 200,000 people had been evacuated in the central island province of Cebu alone.

"Typhoon Hagupit is triggering one of the largest evacuations we have ever seen in peacetime," Denis McClean, UNISDR's spokesman, said.

Forecasters said Hagupit will begin rapidly weakening as it approaches land.

"This is it. I know you are tired, not enough sleep, not enough food, too much coffee," Mar Roxas, Philippines' interior secretary, said a few hours before the typhoon's arrival, calling for a final effort to bring more people from vulnerable coastal homes to safe buildings.

"This is our last push. Every person we can save now is one less we have to look for after the typhoon passes."

Roxas was speaking at a nationally televised planning conference from Samar, having based himself in one of the areas expected to be among the first hit so he could oversee preparations there.

Dozens of domestic flights were cancelled and inter-island ferry services were suspended.