The government declared a state of emergency in southern Songkhla province on Tuesday, as the meteorological department forecast more rain and possible flash floods this week.

Torrential rains since late last week inundated the tourist hub of Hat Yai and the southern region, killing 13 people in four flood-hit provinces, the department of disaster prevention and mitigation said.

Local television footage in recent days has showed rescuers in Hat Yai evacuating people via boats, jet skis and military trucks amid high floodwaters.

Some have used inflatable children's swimming pools to float their kids to safety.

"I was stranded for four days," a woman wearing a rain poncho and holding her baby under an umbrella in the city told local TV station TNN on Monday.

"I decided to leave because I have an infant and I am afraid more water will come," she said.

The woman, her child and her bedridden mother were evacuated by boat, she added.

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

Prime Minister Anutin Charnvirakul told reporters on Tuesday that more boats and trucks would be deployed to aid in evacuations.

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