Thai rescuers on Monday recounted frantic efforts to pluck terrified survivors from the sea after a crowded tourist ferry sank, leaving six dead including three foreigners.

The tragedy raised new questions about safety standards in Thailand, which drew a record 22 million tourists last year but is struggling to shake off a reputation for lax regulation.

Three Thais, one person from Hong Kong and two other unidentified foreigners were among the dead, according to officials in the tourist resort of Pattaya, around 150 kilometers southeast of Bangkok.

The double-decker ferry sank on Sunday afternoon near Koh Larn, a small island popular with day-trippers from Pattaya, a popular beach resort renowned for its racy nightlife.

"The boat went down in minutes. I saw people - some with life jackets, some without - in the water. One man was holding on to a gas cylinder. There was a body face down in the water. They were all panicking, shouting for help," said a local dive guide who was one of the first on the scene.

"We pulled 60 people from the water, including a Russian boy. We gave him CPR, but he was in a very bad way," she said, asking not to be named.

Police said that apart from the six dead, all of the 150 to 200 others on the boat were believed to have been rescued. Nineteen people were injured.

"We don't expect to find any more dead. One Russian boy is seriously ill in intensive care," said Pattaya police chief Colonel Suwarn Chiewnawintawat.

"The captain ran away. We will issue an arrest warrant for him," he said. "Divers will recover the boat today. We still don't know the cause."

Stunned tourists were seen being led to safety on shore on Sunday where they were met by dozens of ambulances along Pattaya's neon-lit beachfront. Medics performed emergency first aid on injured passengers.

Accidents involving boats, buses and other forms of public transport are common in Thailand, where safety standards are generally poor.

On Pattaya's main pier it was business as usual on Monday for the operators of double-decker wooden ferries preparing to take tourists out on day cruises.

"After an accident like this the boats should be grounded for checks but today they are all running," said a European working in the town's marine tourism industry, who spoke on condition of anonymity.

"The boats are very old. There's no maintenance. They are always overcrowded ... there's no head count."

In recent years Thailand's tourist-friendly image as the "Land of Smiles" has also been tarnished by political violence, crimes against foreigners and devastating floods, but visitor numbers continue to rise.

Diplomats from China and the European Union have voiced concern at the number of incidents involving their tourists.

In May more than 100 people were rescued from a tourist ferry that began to sink in rough seas near the tourist island of Phuket.

Two Chinese tourists were killed and several others injured in August when a speedboat in which they were traveling crashed in Pattaya.

Last month an Indian woman died when a boat propeller struck her head while she was parasailing on her honeymoon in the same resort.

Other high-profile safety incidents in the kingdom include a fire at a nightclub in August 2012 on the island of Phuket that left four people dead including two foreigners.

Agence France-Presse