Authorities in Italy have begun the delicate task or refloating the Costa Concordia in what is being described as one of the biggest maritime salvage operations in history.

The vessel hits rocks off the Italian island of Giglio in January 2012 and capsized, killing 32 people.

The wreck was hauled upright in September 2013 but is still partially submerged in the water, resting on six steel platforms.

The next stage of the operation will see air pumped into tanks attached to the ship in order to raise it further in the water.

The process is expected to take up to a week.

The ship will then be towed to its home port, Genoa, where it will be scrapped.

A search for the remains of Indian waiter Russel Rebello, whose body was not recovered from the wreck, will be continued after the vessel was moved.

Hundreds of divers and engineers have been involved in operations to salvage the Concordia.

Captain Francesco Schettino is on trial for manslaughter and abandoning ship, charges he denies.