Strong wind and rain in northern Vietnam unleashed by Typhoon Kai-Tak have killed at least 27 people, damaged thousands of houses and submerged valuable crops, authorities have said.

The typhoon brought winds of about 100kph, according to the national committee on flood and storm control on Monday.

Many of the dead are believed to have been killed in landslides or while attempting to cross rivers swollen by heavy rain.

In the capital Hanoi about 200 trees were uprooted and a huge sinkhole appeared in the middle of a major road.

According to an official update on Monday, more than 12,000 houses were damaged and 30,500 hectares of cropland were flooded nationwide.

The storm was downgraded to a tropical depression on Saturday.

Before slamming into Vietnam, the typhoon killed four people in the Philippines and two in China, where the authorities relocated 530,000 people, according to state media there.