A boy survived the sinking of a tourist boat in Vietnam which killed dozens of people by sheltering in an air pocket of the overturned vessel, it has emerged.

More than 30 people are dead after a tourist boat capsized in Vietnam's Ha Long Bay on Saturday after running into a storm, officials confirmed.

The tourist boat ferrying families around Vietnam’s famed Ha Long Bay was lashed by a sudden storm Saturday in one of the deadliest disasters at the Unesco World Heritage site. The “Wonder Sea” vessel was carrying 46 passengers and three crew members when it capsized because of sudden heavy rain, according to a provincial police report.