A man has died after he was bitten by a shark in waters off the Great Barrier Reef.

Queensland Police said the 23-year-old was in the water with a group of friends off North West Island and he sustained life-threatening injuries to his leg, hand and elbow as he was swimming back to their charter vessel.

The man was flown to Gladstone Hospital in a critical condition about 6pm on Monday but died just after 10pm.

AAP.