This is the dramatic moment a rescue boat struggled against strong floods in southern Thailand, where than 100 people died in the deluge.

The volunteers were setting off to evacuate residents but struggled to operate their speedboat through three-foot floodwaters in Songkhla province on November 26.

Footage shows the pair battling to steady themselves on the vessel with its bow jutting high above the water.

The boat swayed side to side before taking on water, forcing them to turn back.

Onlooker Weeradech Surakamhaeng said: 'Helping is already difficult, more so if you're not skilled at driving a boat. Keep fighting. I'm rooting for all the staff.'

The death toll is expected to breach 100 as catastrophic floods, described by Prime Minister Anutin Charnvirakul as 'the worst flooding in 15 years', swept through the region.

Police Lieutenant General Trairong Phiewphan, Deputy Inspector General of the Royal Thai Police, said 104 deceased victims have been sent for identification on Thursday evening.

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 military has sent some 200 boats, 20 helicopters and its lone aircraft carrier, the Chakri Naruebet, to deliver essential supplies and carry out rescue efforts.

Songkhla's Hat Yai district was among the worst-hit areas, which saw a record 13 inches (335 mm) of rain in a single day on November 21.

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

On Sunday, high-clearance trucks arrived to evacuate more than 400 tourists from flooded hotels across the city.

The Disaster Prevention and Mitigation Department said that floods hit nine southern provinces, affecting some 1,128,284 households and 3,221,958 people.

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 rainstorms in the afternoon leading to widespread flash floods.