PHUKET: Two Cambodian men are in a serious condition in hospital tonight after a pitched battle among vendors that shocked sunbathing tourists at Phuket's Karon beach this afternoon.

Both sides gave different versions of the battle on the beach but a Thai man was under arrest this evening, with three Cambodians also being held at Chalong Police Station in southern Phuket.

The clash came because the Cambodian sunglasses sellers moved from Patong to Karon beach three days ago when the competition from the ''mafia'' on Patong became too intense.

The Cambodian wife of the Thai man told Phuketwan that both rival groups of sunglasses sellers had moved from Pattaya about two years ago. Her husband had operated on Karon since then.

Because the Phuket beaches were proving too tough, she and her husband were now thinking of trying Samui next, she said.

The beach brawl and what it reveals about corruption highlights yet again the need for a single new and honest authority to save all of Phuket's beaches and with them the island's tourism industry.

In Vachira Phuket Hospital tonight in a serious condition are Cambodians ''Gabin'' and ''Wen.''

Thai ''Anan'' Yordjan, 27, said that he had been attacked by 12 Cambodians this afternoon, however Cambodian ''Wan'' Thairak, 32, said that Khun Anan and 15 of his friends had set upon seven Cambodians.

Khun Anan, with a bandage over a wound in the back of his head, told police he had been ambushed by the Cambodians and he beat them back with a length of wood.

Khun Wan said the Cambodians had been forced to move from Patong to Karon three days ago and Khun Anon had been hurling abuse at them ever since.

There were 50 different people selling sunglasses on Patong and the competition was just too tough, Khun Wan said.

The warring groups had migrated from Pattaya two years ago when competition there forced them to move to Phuket.

Khun Wan's Cambodian wife Mon, raised in Thailand, said she and her husband would now probably consider moving to Samui next. It was quieter there, she said.

Both groups bought the sunglasses for 50 baht a pair at a market in an Isarn province and sold them for 200 baht to tourists on Karon and Patong.

Officials and police were bribed to enable them to operate on the beaches, they said.

There was an earlier altercation in September last year between the rival groups when three of the Cambodian group allegedly paid other men to attack Hunsahud, a Cambodian friend of Khun Anan.

Khun Anan said that on that occasion, he rescued Hunsahud but the two men were attacked on their way to Patong Hospital.

Khun Anan later went to police and named Gabin as the leader of the gang of Cambodians.

Phuketwan has called for the Yingluck Shinawatra Government to establish a new authority to oversee all of Phuket's beaches before Thailand's most important tourism assets are entirely overrun by greedy people seeking to commercialise them for their own gain.

Those making the most of the present endemic corruption to privatise Phuket's public beaches range from migrant vendors to expat individuals of high standing and net worth.