2½ Years After It Sank, Italy Cruise Ship Costa Concordia Refloat to Start (PHOTOS)

The final phase of an operation to salvage Italy's ill-fated cruise ship Costa Concordia has began on Monday, two and a half years after it sank off the island of Giglio, claiming 32 lives in the process.

The plan is to raise, tow away the 114,500-tonne vessel to the port of Genoa and then broken up for scrap.

"The most critical phase will be the first day, raising the wreck for the first time. Refloating a passenger ship this large has never been attempted before," South African Nick Sloane, in charge of the salvage operations, told AFP.

Costa Concordia, before it can be towed away for scrapping, has to be first to be refloated by 12 metres. Authorities have filled up some 30 giant hallowed steel tanks or "sponsons" with water and then fitted on the two sides of the ship.

"It is a complex operation never attempted before, but we know we can count on the best technicians in the world," Costa Crociere CEO Michael Thamm said in a statement. "I wish them all the best for the success of this great challenge."

Sloane said the 290-metre cruise ship bore too many cracks. "We know that some of them will get worse when we refloat her. We hope the cracks will stop when we think they will."

Environmentalists are concerned the hull of Costa Concordia could break apart during the salvage operation, and then spill its rotting innards into one of Europe's largest marine sanctuaries.

"Once the ship is removed from our island, no one will be celebrating because even after two years the tragedy of what we witnessed remains. We want this final phase to be over as soon as possible," the Telegraph quoted Sergio Ortelli, the mayor of Giglio.

Rotated upright in September, the ship is now sitting on an underwater platform.

Four decks of the ship are expected to emerge from beneath the waters for the first time since it ran aground in Jan 2012 off the picturesque holiday island of Giglio.