A bridge collapsed leaving villagers stranded amid heavy flooding in northern Thailand.

Footage shows locals building a temporary walkway using bamboo poles after the Ban Nam Sod bridge was wiped out by a flash flood in Nan province on August 22.

Authorities said heavy rain had been lashing Nan province in recent days. The downpours have flooded roads and spilled into farms and homes, forcing residents to leave for higher ground.

Nan governor Chainarong Wongyai said on August 22 that the rain had ceased, though 10 districts in the province remain heavily flooded.

The Thai Meteorological Department had forecasted widespread thunderstorms and heavy rain across northern Thailand, including Nan province.

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.