British tech magnate Mike Lynch and five other people were missing after their luxury superyacht sank during a freak storm off Sicily early on Monday, Italy's civil protection and authorities said. Lynch's wife and 14 other people survived.

Lynch, who was acquitted in June in a big US fraud trial, was among the six people who remain unaccounted for after their chartered sailboat sank off Porticello, when a tornado over the water known as a waterspout struck the area overnight, said Salvo Cocina of Sicily's civil protection agency.

One body has been recovered, and police divers were trying to reach the hull of the ship, which was resting at a depth of 50 metres off Porticello, near Palermo, where it had been anchored, rescue authorities said.

It had a crew of 10 people and 12 passengers, the Italian coast guard said. A sudden fierce storm had battered the area overnight, and struck the place precisely where the 56-metre British-flagged Bayesian had been moored.