Vietnam's death toll from typhoon rises to 233

The death toll in the aftermath of a typhoon in Vietnam has climbed to 233 as rescue workers recover more bodies from areas hit by landslides and flash floods.

Floodwaters from the swollen Red River in the capital, Hanoi, were beginning to recede somewhat on Friday, but many neighbourhoods remained inundated and further north experts were predicting it could still be days before any relief was in sight.

Typhoon Yagi crossed the coast on Saturday, starting a week of heavy rain that has triggered flash floods and landslides, particularly in Vietnam's mountainous north.

Across Vietnam, 103 people are missing and more than 800 have been injured.

Most fatalities have come in the province of Lao Cai, where a flash flood swept away the entire hamlet of Lang Nu on Tuesday.

Eight villagers turned up safe on Friday morning, telling others they had left before the deluge, state-run VNExpress newspaper reported, but 48 others from Lang Nu have been found dead, and another 39 remain missing.

Roads to Lang Nu have been badly damaged, making it impossible to bring in heavy equipment to aid in the rescue effort.

Some 500 personnel with sniffer dogs are on hand, and in a visit to the scene on Thursday, Prime Minister Pham Minh Chinh promised they would not relent in their search for those still missing.

"Their families are in agony," Chinh said.

In Cao Bang, another northern province bordering China, 21 bodies had been recovered by Friday, four days after a landslide pushed a bus, a car and several motorcycles into a small river, swollen with floodwaters.

Ten more people remain missing.

In the aftermath of Yagi, the strongest typhoon to hit the Southeast Asian country in decades, Australia has already begun delivering humanitarian aid supplies as part of $A3 million in assistance.

South Korea has also pledged $US2 million ($A3 million) in humanitarian aid, and the US embassy said on Friday it would provide $US1 million in support through the US Agency for International Development, or USAID.

Experts say storms such as Typhoon Yagi are getting stronger due to climate change, as warmer ocean waters provide more energy to fuel them, leading to higher winds and heavier rainfall.

The typhoon and ensuing heavy rains had damaged factories in northern provinces such as Haiphong, home to electric car company VinFast, Apple parts suppliers and other electronic manufacturers, which could affect international supply chains, the Center for Strategic and International Studies said in a research note.

"Though 95 per cent of businesses operating in Haiphong were expected to resume some activity on September 10, repair efforts will likely lower output for the next weeks and months," the US think thank said.