A pickup truck rolled off the back of a ferry into a river when the driver forgot to set the handbrake.

The vehicle was onboard a vessel travelling from Laos to the Thai province of Bueng Kan near the border on February 1.

However, the pickup slid off the ferry and sank into the Mekong River with its driver still inside.

Rescuers, navy, and marine police rushed to the scene near the Bueng Kan Customs House and pulled the female motorist out of the car.

The Thai woman was safely brought to shore, but was reported to be 'extremely exhausted'. She said she had forgot to the set the handbrake and nodded off once the car was onboard the ferry.

She was taken to the Bueng Kan Hospital for a check-up.

Authorities said they will question the driver and the transport company to determine the cause of the accident.