Thai rescuers pulled 37 bodies from waters off the coast of the holiday island of Phuket yesterday after a tourist boat went down in heavy seas with dozens of Chinese passengers onboard.

Many of the dead were found drifting face down in the water, still wearing life jackets, several kilometres (miles) from where the Phoenix sank after being hit by five-metre (15-foot) high waves in a storm on Thursday evening.

"The death toll today is 37, with 18 still unaccounted for," said a Thai navy official late Friday, requesting anonymity.

In a grisly development earlier, divers reported seeing "over 10 bodies" floating inside the hull of the submerged boat, according to Thai navy Rear Admiral Charoenphon Khumrasee, who said they would try to retrieve them later Friday.

The three-decker boat was carrying 105 passengers, mostly Chinese tourists, when it sank.

"The skies were clear when we went out, we had no idea the weather could change so fast, “ said Wu Jun, 28, from the hospital bedside of his wife Long Hai Ning.

The pair, who were on their honeymoon, were on different decks as the boat started to list, but both managed to escape.

A total of 56 passengers were reported missing as of Friday morning before the recovery effort began, with the Phoenix looking set to be one of the worst boat disasters in recent Thai history.