The captain and crew were rescued from overturned boats as a powerful storm struck off the coast of southern Thailand.

Passing vessels were alerted through the radio that two longtail boats had capsized due to strong winds near Phi Phi Island in Krabi Province on Sunday, July 20.

Without hesitation, they set out at approximately 4:20 pm to assist.

Footage shows rescue teams arriving at the scene, where distressed passengers were seen sitting on the upturned hulls, anxiously awaiting help.

The rescuers quickly manoeuvred their vessel close to each capsized boat and assisted the stranded individuals in swimming over and climbing safely aboard.

All passengers were rescued without injury and brought back to shore safely.

Thailand is among the countries lashed by heavy rain and stormy seas brought by Typhoon Wipha.

In neighbouring Vietnam, a tourist boat was capsized by the storm, leaving dozens of passengers dead. The vessel reportedly overturned after being hit by choppy waves and heavy rain off the coast of Ha Long Bay shortly after 2 pm local time.

The Thai Meteorological Department today predicted more heavy rain and high seas until July 24. It added that around half of Thailand will be battered with increased rainfall due to the typhoon, which made landfall in China's southern Guangdong province on July 20.

Wipha has been downgraded to a tropical storm after hitting mainland China.