British tourists were among 40 people hurt after a collision between two speedboats near a resort in Thailand.

The boats overturned a few kilometres out to sea in the Gulf of Thailand while ferrying people to and from a party on Koh Pha Ngan island beach.

At least two other people were said to be missing in the crash close to Koh Samui island.

The boats collided late on Saturday, throwing passengers into rough waters just off the island, according to local reports.

At least two Britons and four Australians were said to be among the injured, as well as other foreign tourists.

An estimated 25,000 revellers descend on Koh Pha Ngan for the all-night beach rave each month.