A tree toppled over onto a school bus injuring 12 pupils along with the driver and a teacher.

The grey Toyota van had been travelling along the Khao Phanom-Thung Yai Road in Krabi province, Thailand, when a large tree fell on top of it on September 4.

Rescue officers said they received a report of the accident at 4:30pm. They arrived at the scene, where a massive tree trunk lay on top of the van's crumpled roof.

Twelve children and a female chaperone suffered minor wounds while the driver Amornsak, 42, was seriously injured.

He was rushed to a hospital and was still recovering.

Authorities believe recent rains had loosened the soil around the tree's roots, and strong winds blew it over onto the road.

Thailand and neighbouring countries in Southeast Asia are in their annual monsoon rainy season which sees soaring temperatures followed by powerful rain storms in the afternoon leading to widespread flash floods.