The rusty wreck of the Costa Concordia is floating again, as a delicate procedure to move the 114,500-tonne ship away from the coastline of Giglio, Italy, gets underway, salvage teams say.

In what has become one of the largest salvage operations in history, air was pumped into 30 large metal boxes, or sponsons, attached around the hull of the 114,500 tonne ship. The air forced out the water in the sponsons, lifting the vessel off the underwater platform.

"The ship is floating now with its sponsons, and it is held in position by the tugs — maybe you have seen them — there are two tugs that are pulling it east seaward," project head Franco Porcellacchia told a news conference on the island.

Technicians began the complex operation to refloat and tow away the wreck of the Costa Concordia at dawn on Monday morning, 2½ years after the luxury liner capsized off the Italian coast, killing 32 people.

The craggy hulk of the once-gleaming, white, 290-metre ship, which ran aground on rocks near the Tuscan holiday island of Giglio carrying out a display manoeuvre, has been resting on a temporary platform since being righted a year ago.

"I have to say I am very pleased that all the engineering work that has been done beforehand is proven to be very, very accurate, because otherwise we would not be exactly according to plan," said Costa Cruises chief executive Michael Thamm.

"The ship is on even keel, the ship is afloat again. and all technical systems are working very well, so I think we have seen a great start of this refloating operation and let's move forward."

Paying for the disaster, including breaking up the vessel and repairing the damage to Giglio, is likely to cost the ship's owner and operator Costa Crociere, a unit of Carnival Corp, more than 1.5 billion euros ($2.2 billion Cdn), Thamm said.

"The total project costs have exceeded 1 billion euros already and will further go up, because … the cost of this operation we are witnessing here is not included, also the transport to Genoa and the demolition, as well as the remediation of the site. So I believe we will end up at the region of 1.5 billion euro once all is done."

Later Monday, the wreck will be further stabilized with chains and cables, and tug boats will move it about 30 metres into the harbour, where it will be prepared to be towed within days to Genoa in northern Italy, to be scrapped.

Costa Concordia-refloating

A graphic showing what's involved in refloating the capsized Costa Concordia vessel. (Duk Han Lee/CBC)

With files from The Associated Press