Seven people fell into the Po Ko River after a flimsy rope bridge collapsed in high winds.
The victims were driving their motorbikes to Nong Noi Village in the Central Highlands province of Kon Tum at around 2 p.m. when gale force winds snapped the structure sending the drivers tumbling into the waters below.
All of the victims were rescued by locals.
Pham Van Anh, chief of Ngoc Hoi District's Agriculture and Rural Development Division, said the bridge was built in July with a total of VND120 million (US$6,155) in government funds.
The construction was conducted by outside contractors who built it without a designing plan, he said.
The bridge was built following numerous newspaper accounts of school children being drowned or injured as they crossed the river on glider cables.
Last year's floods claimed the original bridge.
Area resident A. Khao, said the bridge should have had nine cables above and seven under.
Instead, it only had seven and two, respectively.
Another local, Nguyen Khac Chin, attributed the accident to shoddy design, saying that the bridge lacked safety joints.