Two Australian brothers surrendered to police over a brutal street attack in Thailand.

Shocking footage shows the siblings and bar security guards appearing to gang up on a tourist in the notorious coastal town of Pattaya on May 26.

Despite nursing an injured face, the defiant holidaymaker - seen in a white unbuttoned white shirt - flashed two middle fingers at his alleged attackers, prompting them to pummel him into the pavement.

Police said the Aussie brothers, Carlos Anthony Madafferi, 25, and Isaac Biagio Madafferi, 20, turned themselves in on Monday evening. They were with two Thai security guards, Theerasak Phungjaingam, 40, and Wongmalai, 35, who allegedly confessed to joining the melee.

Police Lieutenant Colonel Arut Saphanon said: 'We are searching for the other party, who is yet to lodge a complaint. We also recorded the information of the four people who turned themselves in and identified themselves as the perpetrators.

'As for Mr Carlos Anthony Madafferi, who claimed to be the manager of the bar, we will coordinate with immigration police to check whether his work documents are legal or not.

'However, this incident is considered greatly damaging to the tourism image of Pattaya. One of the suspects is a manager who committed violence despite the government's measures. We intend to take strict legal action against him.'

Carlos said the injured tourist had tried to dodge his bill after drinking at the bar. He claimed he tried to take his phone as collateral, but was punched in the head, sparking the brutal attack.

He said: 'I retaliated because he punched me first. The security guards arrived to drag him away, but he continued provoking me, leading to the fight outside the bar.'

Police said that the incident could result in the bar being closed. They said the details would be given to the local council to make a decision on.

Former fishing village Pattaya became popular with American troops on 'rest and relaxation' breaks in the 1950s and 1960s when the US military had bases in Thailand while fighting Communism in Vietnam. Rural families are said to have even dressed their sons as women to cash in on the gold rush.

The handful of bars in the coastal town quickly grew and it is now the world's biggest sex holiday destination, with round-the-clock prostitution and drugs - a modern-day Sodom and Gomorrah rife with crime and debauchery.

Government chiefs have attempted to clean up the city but regular violence, depravity and claims of corruption continue to blight its reputation.