A tour bus flipped over killing one passenger and injuring 28 more in western Thailand.

The double-decker tour bus was descending along the Khao Tap Tao route when it lost control on the curved road and flipped over a concrete barrier in Kanchanaburi province on April 28.

Police Lieutenant Weerayut Chuayjan of the Si Sawat Police Station said cops received a report at 12:20 pm.

He said: 'After being notified, police coordinated with Phithakkan Foundation rescue official, Tha Kradan Hospital and Erawan Subdistrict authorities to help injured people at the scene.

'A white double-decker tour bus with registration number 30-1418 Saraburi was found overturned across the barrier and lying on its side.

'Dozens of people were on the roadside waiting for help. They were given first aid before being rushed to the Tha Kradan Hospital and Erawan Subdistrict Health Promoting Hospital.'

One passenger, identified in reports as Mana Aunlamai, was crushed in the bus wreckage.

A survivor said the group was composed of factory workers from Ayutthaya who had rented the bus for a rafting trip in the province. They were returning to Ayutthaya when a burning smell was detected inside the bus as it was going downhill, shortly before the vehicle lost control.

The driver Phakorn Maithong, 24, suffered light injuries and claimed the brake system had malfucntioned.

Police Lieutenant Weerayut said the exact cause of the accident was being investigated.

Khao Tap Tao in Kanchanaburi is an accident-prone area due to its steep and winding roads. The unfamiliar terrain may cause brake malfunctions for inexperienced drivers travelling along the route.