Tourists were injured when their minibus rolled downhill on a mountain road in Thailand.

The passengers had been buying souvenirs at a shop and were climbing back into the vehicle when it began to slide on the sloped road on Doi Suthep mountain in Chiang Mai on September 23.

Dramatic footage shows the van, its door open with the screaming tourists inside, accelerating along the tarmac without anyone to steer the wheel.

The frantic driver and onlookers ran after the minibus, which stopped after hitting onto a small mound on the roadside.

The shaken tourists emerged from the van with minor injuries.

The unnamed driver said he had engaged the handbrake and opened the minibus door to allow the passengers to buy souvenirs.

It is believed the brakes had failed when the tourists returned to the van, with their combined weight launching the vehicle downhill.