Two French tourists driving a luxury sports car have been arrested over a attack on a local in Thailand.

The foreigners - VINCENT RAYMOND BUGEYA, 34, and JULIEN GERARD RENE, 28 - were detained on the holiday island of Koh Samui in Surat Thani province on October 16 after allegedly beating a villager, Somkhuan Songkhot, 43, while he was trying to help them.

The pair had been driving a white Porsche sedan with a red license plate - indicating it was brand new - when they met Somkhuan and his wife, Lakkhana, 47, on the road leading to Chaweng Beach on October 15 evening.

Lakkhana said her husband had just fetched her from the Central Samui shopping mall where she worked as a cleaner when the French nationals began chasing after them while honking the car's horn.

Thinking the tourists were lost, Somkhuan alighted from his motorcycle reportedly to give directions but was punched in the face, knocking him out cold.

The French men then hopped back into their Porsche as shocked onlookers flocked towards the unconscious local, who was rushed to a hospital.

Somkhuan is currently battling for his life after suffering a brain haemorrhage. He is still unresponsive after brain surgery in the hospital, local media reported.

Eyewitness Theerayut Sritin, 24, an employee of a restaurant near where the brutal attack occurred, said: 'The motorcycle and foreign car came to a stop on the sidewalk in front of our shop. At that moment, a foreigner opened the car door and approached the Thai man angrily before physically assaulting him. The Thai man fell and bled onto the pavement.'

Lieutenant Colonel Sirach Kamuni, Deputy Inspector General of Investigation for the Bo Phut police, said: 'The accused have been detained on charges of causing grievous bodily harm.'

Both of them were denied bail for the barbaric assault, he added.