The typhoon blew into Dinalungan town in Aurora province on Sunday night after setting off fierce rain and wind in northeastern Philippine provinces all day from offshore, with sustained winds of up to 185 km/h and gusts of up to 230 km/h.
The biggest typhoon to threaten the Philippines in years, Fung-wong could cover two-thirds of the archipelago with its 1800km-wide rain and wind band, forecasters said.
It approached from the Pacific while the Philippines was still dealing with the devastation wrought by Typhoon Kalmaegi, which left at least 224 people dead in central provinces on Tuesday before pummelling Vietnam, where at least five were killed.
A villager drowned in flash floods in the eastern province of Catanduanes and another died in Catbalogan city in eastern Samar province when she was hit by debris, officials said.
Philippine President Ferdinand Marcos Jr has declared a state of emergency due to the extensive devastation caused by Kalmaegi and the expected calamity from Fung-wong, which is also called Uwan in the Philippines.
Tropical cyclones with sustained winds of 185 km/h or higher are categorised in the Philippines as a super typhoon, a designation adopted years ago to underscore the urgency tied to more extreme weather disturbances.
"The rain and wind were so strong there was nearly zero visibility," Roberto Monterola, a disaster-mitigation officer for Catanduanes, told the Associated Press by telephone.
Despite calls for residents to leave on Saturday, some still stayed on.
"Our personnel rescued 14 people who were trapped on the roof of a house engulfed in flood in a low-lying neighbourhood," Monterola said.
"A father also called in panic, saying the roof of his house was about to be ripped off by the wind. We saved him and four relatives."
More than a million people were relocated from high-risk villages in northeastern provinces, including in Bicol, a coastal region vulnerable to Pacific cyclones and mudflows from Mayon, one of the country's most active volcanoes.
Defence Secretary Gilberto Teodoro Jr warned about the potentially catastrophic effect of Fung-wong in televised remarks on Saturday.
He said the storm could affect a vast expanse of the country, including Cebu, the central province hit hardest by the previous typhoon, and metropolitan Manila, the densely populated capital region.
More than 30 million people could be exposed to hazards posed by Fung-wong, the Office of Civil Defence said.
Teodoro asked people to follow government orders and seek shelter away from villages and towns prone to flash floods, landslides and coastal tidal surges.
"We need to do this because when it's already raining or the typhoon has hit and flooding has started, it's hard to rescue people," Teodoro said.
The Philippines is battered by about 20 typhoons and storms each year.
The country also is often hit by earthquakes and has more than a dozen active volcanoes, making it one of the world's most disaster-prone countries.
