Residents formed a human chain to rescue an elderly neighbour who was trapped inside a building during a flood.

The pensioner was caught in the waist-deep torrents that engulfed large parts of the island of Phuket, Thailand, following heavy rain on June 30.

Footage shows how the man was trapped inside a building and unable to leave safely, prompting the operation of forming a human chain to rescue them.

A group of locals gathered before a dozen Burmese workers living nearby arrived in a ten-wheeler truck and waded through the flood to enter the building and rescue the employee.

Despite the continuing rain, they formed a line to safely evacuate the employee.

Flights to the Phuket International Airport were diverted to neighbouring cities as well as to the capital Bangkok and across the border to Langkawi and Penang in Malaysia. Officials said the rain was so violent that pilots could not see the runway.

Natural disaster chief Sophon Thongsai said that flooding was the worst in the northern part of the island in the Thalang district.

Forecasters warned the rain would continue throughout the day before proceeding on Monday.

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.