Vietnam evacuated thousands of people from central and northern provinces Sunday as Typhoon Bualoi raced toward the country faster than expected with landfall forecast later in the day.

Bualoi had left at least 20 people dead in the central Philippines since Friday, mostly from drownings and falling trees, and knocked out power in several towns and cities, officials said.

The storm forced about 23,000 families to evacuate to more than 1,400 emergency shelters.

The typhoon was expected to bring winds of up to 133 kph (83 mph), storm surges of more than a metre (3.2 feet) and heavy rains that could trigger flash floods and landslides.

Vietnam's weather agency said Bualoi was about 200 kilometres (124 miles) east of central Vietnam early Sunday and moving northwest. It was expected to make landfall between Quang Tri and Nghe An provinces.

Authorities grounded fishing boats in northern and central regions and ordered evacuations. State media reported Da Nang planned to relocate more than 210,000 people, while Hue prepared to move more than 32,000 coastal residents to safer ground.

The Civil Aviation Authority said operations were suspended at four coastal airports, including Danang International Airport, with several flights rescheduled.

Heavy rains have drenched central provinces since Saturday night. In Hue, floods swamped low-lying streets, storms ripped off roofs and at least one person was reported missing after being swept away by floodwaters.

In neighbouring Quang Tri province, a fishing boat sank and another was stranded while seeking shelter. Eight people have been rescued while efforts were underway to reach three others at sea, state media said.

Forecasters warned of more heavy rain through October 1, raising risks of flooding and landslides in northern and central provinces.

Bualoi was the second major storm to threaten Asia in a week. Typhoon Ragasa, one of the strongest to hit in years, left at least 28 deaths in the northern Philippines and Taiwan before making landfall in China and dissipating Thursday over Vietnam.

Global warming is making storms like Wipha stronger and wetter, according to experts since warmer oceans provide tropical storms with more fuel, driving more intense winds, heavier rainfall, and shifting precipitation patterns across East Asia.