Rescuers evacuated a bedridden man and a toddler who had spent days stranded on a rooftop as floodwaters surged through southern Thailand.

The trapped residents had fled to higher ground during the flood crisis in Songkhla province. The deluge has killed more than 100 people across the region.

Volunteers on a relief mission found the partially paralysed man sprawled on a roof on November 26.

Footage shows officers carefully making their way across the flimsy metal sheets to reach him. The operation proved painstaking, as the man was unable to move on his own.

They strapped him onto a rescue board and slid him down the sloped roof toward their boat before taking him to a hospital.

The team continued rescue efforts until the evening, braving fast-moving floods as they rowed through inundated neighbourhoods.

They later spotted a family stranded on the second floor of their home.

The desperate parents pleaded for help to evacuate their toddler, aged around two or three, who had recently undergone surgery on the right leg.

The youngster was passed through a window along with her belongings. The rescuers ferried her to an evacuation centre.

The death toll has climbed to more than 100 as catastrophic floods, described by Prime Minister Anutin Charnvirakul as 'the worst flooding in 15 years', swept through southern Thailand.

Government spokesman Siripong Angkasakulkiat said: 'There have been 33 deaths across seven provinces. Causes of death include being swept away by currents, drowning, electrocution, and landslides.'

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 rain storms in the afternoon leading to widespread flash floods.