Two scuba divers of Italian Navy inspect inside the Costa Concordia cruise ship
Two scuba divers of Italian Navy inspect inside the Costa Concordia cruise ship. (Reuters)

The Costa Concordia cruise liner was beset by structural problems that affected its balance and made it easier to sink, Captain Francesco Schettino's defence lawyer has claimed.

The ship's balancing pump and ballast had inbuilt structural problems, an allegation that will be proven by the Voyage Data Recorder (VDR), the defence lawyers said.

The liner's owner, Costa Crociera, is already under fire for the shipwreck. "There were several problems and an unpardonable carelessness," general prosecutor Beniamino Deidda said.

Oil salvage operations were under way, more than 10 days after the ship ran aground off the Italian coast. Specialists from Smit, a Dutch firm best known for raising the wreck of the Kursk Russian submarine, were expected to pump out more than half a million gallons of fuel oil from the ship. The operation was expected to take between four and six weeks and involved 40 engineers.

Divers searching the cruise liner claimed that the smell of decomposing bodies inside the ship had become unbearable and the air "unbreathable".

"Imagine the scene if you went on holiday and you came back to find the fridge had switched itself off. The divers are working in those conditions," fire chief Enio Aquilino told the Daily Mail.

Rescue squads found the bodies of two women in a submerged area of the ship. One was said to be Maria d'Introno, 30, who was on a honeymoon with her husband.

Civil protection official Franco Gabrielli said that the ship was stable and would not sink. "Rescue operations will go ahead," he said. He updated the death toll to 15 people with 24 still missing.