The accident occurs at 4:50am on the Long Thanh-Dau Giay Highway after a tour bus is rear ended by a second bus causing it to flip into the path of a semi-truck and trailer.

All three vehicles are heading in the same direction at the time of the crash. 

The big rig driver, not hauling any freight, had only moderate injuries. The tour buses regularly ferry travellers from Dong Nai Province to Ho Chi Minh City.

Seventeen people on board the buses sustain injuries, five seriously, and are rushed to local emergency centres.

The sole fatality is identified as Nguyen Van No, 30, from Quy Nhon City in Binh Dinh Province.

Authorities are continuing to investigate the accident.