Thousands of locals were evacuated as record floods ravaged southern Thailand, killing at least 13 people.

Residents fled to relief centres during the devastating deluge in the city of Hat Yai in Songkhla province.

Songkhla Governor Ratthasart Chidchoo on Monday declared all 16 districts disaster zones and ordered the immediate evacuation of children, the elderly and the sick.

He said he had ordered the setup of two Royal kitchens in Hat Yai, as well as water pumps, rescue boats, and trucks to evacuate residents.

A day earlier, high-clearance trucks arrived to evacuate more than 400 tourists from flooded hotels across the city.

Soldiers, volunteers, and local government units have also been mobilised to hasten relief efforts, but they were hobbled by limited phone signal in the area.

The Thai navy said it was preparing to deploy 14 boats and the aircraft carrier Chakri Naruebet to southern Thailand, with medical teams, supplies, and field kitchens able to supply 3,000 meals a day.

The navy said in a statement: 'The fleet is ready to deliver forces and carry out actions as the Royal Navy orders.'

The Department of Disaster Prevention and Mitigation said some 1.9 milion people were affected.

Authorities said at least 13 people have been killed in the catastrophic floods, described by Prime Minister Anutin Charnvirakul as 'the worst flooding in 15 years'.

The Southern Eastern Meteorological Centre said a strong monsoon trough was causing the heavy rainfall, which was expected to ease this week.

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.