The holidaymaker became trapped while diving between Comino's underwater caves. [Reuters]

A 20-year-old British holidaymaker has died while swimming on the Maltese island of Comino.

It is reported that the man got into difficulties while diving with his parents in Comino's underwater caves - which are among the most popular scuba destinations in the world.

The man was diving in between the caves when he became stuck in rocks, and was unable to free himself before drowning.

A number of local divers attempted to extricate the victim, but it took several attempts to free him.

Both the victim and his father were eventually transferred by army helicopter to the Mater Dei Hospital in the city of Msida, Malta. The father is reported to be suffering from shock.

News of the fatality comes just five days after two British men were evacuated from Comino, also by armed forces helicopter, when both began to suffer chest pains.

It also follows the death of five-year-old Lara Lewis and her 66-year-old grandfather Brian O'Dwyer off Portugal's Salgado beach on 22 August.