HANOI -- Vietnamese authorities warned on Monday of the risk of floods and landslides triggered by Tropical Storm Conson, even after the low-pressure system weakened off the country's central coast at the weekend.

Heavy rain brought by the storm killed one person, damaged 31 houses and flooded more than 1,000 hectares (2,472 acres) of rice fields in central Vietnam, the country's disaster management agency said.

Last week, the authorities put 500,000 soldiers on standby, readied evacuation plans and ordered vessels to stay in port as the country braced for the arrival of Conson.

"Areas from Quang Binh to Quang Ngai and Kon Tum are facing the threat of landslides and floods," Vietnam's weather agency said in a statement, referring to central coastal areas and Kon Tum in the country's central highlands.

No damage has been reported so far to the coffee farms in the Central Highlands, the country's main growing belt.

"The coffee farms are safe and we expect to start harvesting from November," coffee grower Tran Dinh Trong from the Central Highlands province of Dak Lak said.

Vietnam is prone to destructive storms and flooding due to its long coastline. Natural disasters - predominantly floods and landslides triggered by storms - killed 379 people and injured 1,060 others in the country last year.

Separately, Typhoon Chanthu, which at one point was categorised by the Philippine weather bureau as a category 5 storm, weakened after hitting the northernmost region of the Philippines on Saturday, its weather bureau said. 

Authorities in Shanghai and neighbouring coastal regions have cancelled flights, and suspended schools, subways and trains as Chanthu approached China after drenching Taiwan though causing little damage there.