The wreck of the Costa Concordia cruise ship is prepared to be towed away near the port of Giglio Island on Monday.

AFP

A mammoth operation to refloat the shipwrecked Costa Concordia began on Monday in Italy, with salvage workers attempting to raise the rusty liner from its watery grave on the shores of a rugged Tuscan island.

"I am a bit nervous," said Salvage Master Nick Sloane as he headed out to the wreck to oversee the first-ever operation to float a ship of such size, two and a half years after it sank in a nighttime disaster that left 32 people dead.

"Today we'll see whether our calculations were correct," the sandy-haired mariner said.

Media crews from around the world crowded onto the port to see off the globe-trotting South African, who was dressed in his trademark casual blue jeans with a red life jacket over a black T-shirt.

The liner - twice as big as the Titanic - will be refloated over a six-to-seven day period and then be towed away for scrapping to a port in Genoa in northern Italy, where it is expected to arrive later this month.

The 114,500-tonne vessel will be raised two metres on Monday off the artificial platform on which it has rested since it was righted in September.

"The first phase this morning was to ease the ship and reduce the weight on the platform," Michael Thamm, chief executive of ship owner Costa Crociere said, as giant yellow cranes took a load of around 8,000 tonnes off the vessel.

Lifting the wreck will then begin from the stern, he said, as navy officials and the head of Italy's civil protection agency scrutinised the latest operation details on a terrace dotted with palm trees in front of the ship.

Fears of a bad turn in the weather forcing a halt to the operation before it began were quelled as the rain cleared at dawn and tug boats carrying divers and engineers sped out to the Concordia to be on hand for emergencies.

Air will slowly be pumped into 30 tanks or "sponsons" attached to both sides of the 290-metre Concordia to expel the water inside and raise the ship.

It will then be towed away from the shore and moored using anchors and cables. Thirty-six steel cables and 56 chains will hold the sponsons in place.

"The risks are that the ship could bend as it is raised, or the chains underneath it could snap," Sloane told AFP before the operation.

"There will be 42 people on board during the first manoeuvre. If disaster strikes we will evacuate through emergency escapes on the bow and stern," he said.

If all goes well, all the sponsons would be lowered into position on Tuesday and Wednesday.

"That will be the point of no-return," senior engineer Franco Porcellacchia told reporters on the island on the eve of the operation.

 The Concordia crashed off Giglio on the night of January 13, 2012, forcing many of its 4,229 passengers and crew from 70 countries to jump into the sea as lifeboat pulleys failed.

The ship's captain Francesco Schettino is on trial for manslaughter, causing a shipwreck, and abandoning the vessel before all passengers had evacuated.

The body of Indian waiter Russel Rebello is still missing and there will be a search for his remains during the refloating.