A bus overturned and crashed in northern Vietnam on Saturday, killing nine people and injuring another nine, state media reported.

Most of the 18 passengers were teachers from Hanoi on a charity trip to Lao Cai province, where the accident occurred on a long downhill stretch in Phinh Ho commune.

Rescue workers used specialised equipment to pry survivors from the wreckage, the local Lao Cai newspaper reported.

Local authorities were investigating the cause of the crash, it said.

Fatal road accidents, often involving buses or trucks, are common in Vietnam. They are often caused by speeding or mechanical failure.

According to finance ministry figures, 8,515 people were killed and 10,204 others injured in road accidents in the first 10 months this year. (AFP)