Thai authorities on Friday warned of flash floods across the south as torrential rains lashed the region leaving at least six people dead, delaying flights and disrupting holidays during peak tourist season.

Nine provinces along Thailand's southern tail have been hit by unseasonal rains for nearly a week, with the resort islands of Samui and Phangan deluged, leaving thousands of tourists stranded or delayed.

Six people have been killed and at least 120,000 households have been affected by the flooding across the south, the Interior Ministry said in a statement, where waters have turned roads into rivers and upended rail tracks.

In a statement on Friday the Thai Meteorological Department warned residents and visitors to the south of possible "heavy rain and flash floods" with downpours expected to continue for two more days.

Photos circulating on social media showed cars and motorcyclists plying through muddy, waist-high waters.

A smattering of foreign tourists on Samui took advantage of the flooded streets, drawing bemused looks from locals as they bobbed along in inflatable tubes sipping beers. 

Tuula Fitzpatrick, the owner of Moby Dick guesthouse near Samui's main party strip, said the flooding was the worst to hit the island in over a decade.

"In our guesthouse there were lots of people whose flights were cancelled," she told AFP.

"I've been living here for 12 years and I've never seen it so bad... It was scary. Some of my staff couldn't come to work."

Rail services have also been disrupted on the mainland, with trains unable to pass through the flooded region. 

"The flood waters have hit the tracks and in some places the track was washed away," said Thanongsak Kongprasert, deputy governor of the State Railway of Thailand. 

The main airport in Nakhon Si Thammarat province has been shuttered because of a flooded runway, affecting at least 26 flights, the transport ministry said.  

Junta chief Prayut Chan-O-Cha arrived in the southernmost province of Narathiwat on Friday to hand out flood relief and meet officials.   

Across the border in northern Malaysia more than 15,000 people remained stranded in relief centres after days of tropical downpours as thousands more headed home to survey the damage wreaked by the floods. 

"The weatherman has predicted no more heavy rain. More relief centers are being closed but we remain on alert," Amir Sarifudin, Terengganu state civil department force deputy director told AFP.

But frustration mounted among those stuck in relief centres as evacuees complained of their inability to work and provide for their families. 

"I usually earn about 50 ringgit ($11) daily. Now I only have 15 ringgit in my pocket for my family of four," Mohamad Zain Sapein, a labourer from northern Kelantan state, told AFP.

The rains are unusually heavy for this time of year, with most of Thailand normally experiencing a cooler, dry period from early November through January -- a three-month long peak tourist season that is crucial to the economy.

Source: AFP