A father and son were killed after being swept away by floodwaters in the north central Nghe An Province on Saturday, the National Steering Committee on Natural Disaster Prevention said on Sunday.
The two, aged 59 and 34, were picking firewood along a river near their home in Cam Muon Commune in Que Phong District when it happened.
In Hoa Binh Province, around 270 km north of Nghe An, a person was killed in a house collapse due to landslides early on Sunday.
Since Saturday the central region has received downpours of 70-150 mm due to a combination of a cold spell, an intertropical convergence zone and windward terrain of the Annamite Range.
As of Sunday evening at least three other people were missing in Quang Binh and Quang Tri Provinces as rivers overflowed, streets turned into streams and daily life was disrupted. More than 1,000 houses in Quang Binh have been flooded and dozens of others in Quang Nam Province damaged.
According to the National Center for Hydrometeorological Forecasting, on Monday the area between Nghe An and Thua Thien Hue provinces will receive 50-130 mm of rainfall, including 150 mm in some places.
It warned this could trigger flash floods and landslides in mountainous areas and more flooding in low-lying and riverine areas.