Thousands of people are sheltering ‌in evacuation centres in Bangkok after a weekend of intense rain that has wreaked havoc across the Thai capital and surrounding areas.

Entire neighbourhoods were inundated and the drainage network swamped after 320 millimetres of ‌rain fell in two or three days – nearly as much as the sprawling low-lying city usually gets in all of September.

“Over 80,000 residents living in flooded areas are unable to leave their homes,” Unsit Sampuntharat, the permanent secretary of the interior ministry, said on Monday, adding that mobile kitchen and boats were being mobilised in relief efforts.

“The goal is to provide three meals a day to ‌all residents throughout the … flooding ‌period and for ⁠at least another seven after waters recede,” he said, amid intermittent showers on Monday.

Bangkok is among 41 provinces across Thailand hit by floods since September 16 that killed at least eight people and disrupted more than 580,000 homes, the ministry said.

The floods could cause economic damage of at least 11 billion baht ($A466 million) nationwide, with the losses likely to rise unless the situation improved, said Aat Pisanwanich of Rangsit University’s economics department.

In the capital’s hard-hit neighbourhood of Bang Kapi, residents waded through waist-deep waters to buy essentials from vendors, some of whom ​set ​up stalls with floating plastic boxes and drums, three days ​after incessant rain brought floods.

The Bangkok Post reported that a man who drove a jet ski through the floodwaters, deliberately making waves along a flooded main road, had been arrested and charged with causing a public nuisance.

Video circulating on social media showed the man, later identified as 27-year-old Sorn Keadsiri, accelerating and making sharp turns, sending waves towards homes and roadside structures.

He was later fined, given a suspended jail sentence and placed on a year’s probation by a court.

Elsewhere, a city administration official said nearly 6000 people had been moved to 234 evacuation centres.

Sitting on a river delta of soft clay just 1.5 metres above sea level, heavily built up Bangkok is sinking by several millimetres a year. Its population of more than 8.4 million often battles floods in its six-month-long rainy season.

Further east, in the coastal province of Rayong abutting a major industrial belt, authorities ordered evacuations on Monday after flood waters swelled ​two reservoirs beyond their capacity.

Thailand’s Disaster Prevention and Mitigation Department said floodwater levels continued to rise in almost half of the 27 inundated provinces, and a new warning was also issued for people living downstream from the Mae Klong River Dam in Kanchanaburi, to the west of the capital.

In 2025, catastrophic southern floods in 2025, triggered by 630 millimetres of rain over three days, killed at ​least 145 in Thailand, inundated more than 33,000 homes ⁠and damaged critical facilities such as schools, hospitals and highways.

-with AAP