Flash floods in southern Thailand washed out a bridge on the country's main north-south highway on Tuesday, backing up traffic for 200 km (125 miles) as the death toll from days of unseasonable rain rose to 25, local media reported.

More than 360,000 households, or about a million people, have been affected by the floods that have damaged homes and schools and affected rubber and palm oil production, the Department of Disaster Prevention and industry officials said.

Television pictures showed abandoned cars submerged in murky waters in Prachuap Khiri Khan province where a torrent washed out a bride on the main road linking Bangkok to the south, causing the 200 km tailback, media reported.

The railway link to the south, and Malaysia, beyond has been severed for days.

Thailand's rainy season usually ends in late November but this year heavy rain has fallen well into what should be the dry season.

Southern Thailand is a major rubber-producing area and the wet weather has hit production. Palm oil plantations have also been flooded, industry officials and farmers' groups said.

In Nakhon Si Thammarat, one of the worst-hit provinces, television footage showed villagers commuting by boat.

Thailand Flood Show all 13 1 /13 Thailand Flood Thailand Flood Thai soldiers in a boat approach a flooded village road in the Chaiya district of Thailand's southern province of Surat Thani Getty Thailand Flood Thai soldiers in boats inspect the water depth in front of a flooded village in the Chaiya district of Thailand's southern province of Surat Thani ge Thailand Flood People stand by the edge of a flooded field after Thai soldiers drop emergency supplies to their village in the Chaiya district of Thailand's southern province of Surat Thani. Overland routes to Thailand's flood-hit south were severed after two bridges collapsed following days of torrential rain that has killed at least 25 people, including a five-year-old girl Getty Thailand Flood A bridge damaged by floods is pictured at Chai Buri District, Surat Thani province, southern Thailand Reuters Thailand Flood A bridge damaged by floods is pictured at Chai Buri District, Surat Thani province, southern Thailand Reuters Thailand Flood A rescue boat and a helicopter moving towards a group of stranded people in the Srinakarin district of the southern Thai province of Phattalung Getty Thailand Flood A Thai villager rows a boat past a flooded Buddhist temple in Nakhon Si Thammarat province, southern Thailand EPA Thailand Flood Thai villagers wade through floodwaters at a village in Nakhon Si Thammarat province, southern Thailand EPA Thailand Flood An aerial view of a residential area that is submerged by floodwaters in a southern province of Thailand EPA Thailand Flood People inspecting the damage of a collapsed road due to heavy flooding in the Sichon district of the southern Thai province of Nakhon Si Thammarat Getty Thailand Flood Residents stand in floodwaters in the southern Thai village of Chauat Getty Thailand Flood Women look out from a flooded house in the southern Thai village of Chauat Getty Thailand Flood A man rides his motorbike on the rear wheel in floodwater at Tumpat district, near the Thailand border, Kelantan, Malaysia EPA

"It's like a big pond," said resident Pattama Narai.

Nakhon Si Thammarat has had 493 mm of rain in the past seven days, 426 mm more than the average for this time of year, according to Thomson Reuters data.

Flooding regularly occurs in the May-November rainy season.

In 2011, widespread flooding that began in the north and flowed down to Bangkok crippled industry, killed more than 900 people and slowed economic growth to just 0.1 percent that year.