This is the shocking moment a house on a riverside collapsed due to raging floodwaters in Thailand.

The structure's foundation had been eroded by the deluge raging through the Kham River and subsided in Chiang Rai province on August 18.

Footage shows chunks of the banks crashing into the fast-flowing water before the concrete block of a home plunged.

The water carried away its metal roof and crumbled walls while residents from nearby homes rushed to evacuate.

The National Water Resources reported that Chiang Rai received 120 millimetres of rain that day, flooding homes.

Officials at the Department of Disaster Prevention and Mitigation said the flood affected at least 2,000 households in the province.

Thailand and neighbouring countries in Southeast Asia are at the start of their annual monsoon rainy season, which sees soaring temperatures followed by powerful rain storms. The rudimentary infrastructure often struggles with the deluge, leading to widespread flash floods.