"Authorities say 33 people have died across seven provinces, with causes including flash floods, electrocution and drowning," government spokesman Siripong Angkasakulkiat told reporters.

"The water level is expected to recede in the south."

The government declared a state of emergency in southern Songkhla province on Tuesday, with torrential rains since late last week inundating the tourist hub of Hat Yai and the southern region.

More than 1,200 people have been evacuated from their homes in Songkhla since Thursday, the province's public relations department said.

Thailand regularly records heavy rainfall from June to September, but experts say human-induced climate change has intensified extreme weather, making conditions increasingly unpredictable.