On Friday, local television broadcast images of dozens of divers searching for the missing, while more rescuers were on standby at a nearby pier. The seas were calm and the skies were clear, according to a Reuters report.

"Right now, officials from the Marine Police and Navy are helping to dive at the spot where the boat sank," the Thai Marine Police said in a statement. "They are diving to a depth of about 40 meters."

A Marine Department official said there was probably "no chance" that any more survivors would be found inside the boat, the Reuters report said.

"A day and a night has passed," said the department's deputy director-general, Kritpetch Chaichuay.

Ni Minghao, a 38-year-old Chinese who runs a travel agency in Phuket, said many volunteers from local travel agencies who speak both Chinese and Thai have participated in the rescue and treatment work, offering translation services in hospitals where the Chinese survivors and the injured were receiving medical treatment.