Tens of thousands of people were forced to flee their homes on Tuesday as massive floods inundated northern Vietnam in the wake of Typhoon Yagi, while the death toll climbed to 127.

Yagi struck Saturday bringing winds in excess of 149 kilometres per hour and a deluge of rain that has caused flooding not seen in decades, according to locals.

More than 59,000 people have been forced to evacuate their homes in Yen Bai province, local authorities said on Tuesday, after the floodwaters engulfed almost 18,000 homes.

Floodwaters in Hanoi have reached levels not seen since 2008, state media reported, citing a senior local official, and forecasters have warned more is expected in the city's historic centre.

Phan Thi Tuyet, 50, who lives close to the swollen and fast-moving Red River which runs through the capital, said she had never experienced such high water.

"I have lost everything, all gone," she told AFP, clutching her two dogs as she was evacuated by boat, along with other residents whose homes were flooded.

"I had to come to higher ground to save our lives. We could not bring any of the furniture with us. Everything is under water now."

Typhoons in the region are forming closer to the coast, intensifying more rapidly, and staying over land longer due to climate change, according to a study published in July.

Yagi downed bridges, tore roofs off buildings, damaged factories and triggered widespread flooding and landslides.

The north of the country, densely populated and a major manufacturing hub for global tech firms including Samsung, was badly hit, with floodwaters in the city of Yen Bai at record levels, meteorologists said.

Authorities have issued flood and landslide warnings for 401 communes across 18 northern provinces.

As well as the dead and missing, flooding and landslides have also injured at least 752 people, officials at the ministry of agriculture said on Tuesday. (AFP)