Italian officials have expressed fears of an environmental disaster in an area of outstanding natural beauty as bad weather brought rescue work on the  wrecked Costa Concordia cruise ship to a halt amid choppy seas today.

"This is an ecological timebomb," Sergio Ortelli, mayor of the picturesque Tuscan island where the luxury Costa Concordia liner hit underwater rocks and keeled over on Friday with more than 4,200 passengers and crew aboard.

Ortelli said there were 2,380 tons of fuel on the ship. "This is the second worry after human lives," he said, as crews began putting down anti-spill booms.

"I hope that the fuel can be taken off the ship soon and maybe the ship can be removed too because it is hampering navigation," he said.

"We are monitoring constantly but there has been no spill so far," he added.

However Rodolfo Raiteri, the head of the coastguard diving teams searching for survivors, said the ship had shifted nine centimetres (four inches) and the divers had been called off for the time being.

Fifteen people were still feared trapped in the wreckage after the disaster which left at least six dead.

Famous for its sandy beaches and rustic charm, Giglio is a major holiday destination in the summer when the population swells from around 800 permanent residents to some 5,000 people and is dotted with exclusive villas.

The island is also a major marine sanctuary and popular for whale-spotting.

Local officials are calling for new rules imposing strict limits on navigation in the area and in particular an end to the practice of "showboating" when cruise ships file past close to the island.

The owner of the ship, Costa Cruises, has been instructed by coastguards "to remove the wreck of the ship and avoid any spill of oil into the sea," said Filippo Marini, head of the local coastguard press office.

"We are putting in place booms right now but so far there hasn't been any leak. There is maximum attention on the environmental problem. We are all working together to resolve this as soon as possible," he said.

Representatives of two ship salvage companies, US-based Titan Salvage and Netherlands-based Smit -- the biggest European player in the industry, were already on the island waiting for a contract to begin operations.

One of the men, who declined to be named, said the contract could run into the millions of euros (dollars) but that the process of pumping fuel out of the tanks could only start later this week after all the equipment is in place.

He also said the actual removal of the ship could take weeks and excluded the possibility that it could be cut up on site but said the details of how exactly the 114,500-tonne wreck could be taken off the shore were confidential.

"They've been phenomenally lucky there's been no spill. If the hole in the hull had been four or five metres further along it would have punctured the tanks," he said after a series of meetings with local port authorities.

"The conditions are still okay. We have to move as soon as possible before the weather gets worse," he said, as the wind picked up on Monday for the first time since the accident, making for choppy conditions at sea.

"It's very close to the edge of much deeper water," said the man, explaining that the waves could push it off its resting place and it could sink entirely.

The salvage company representative explained that the fuel pumped out would be replaced by water in the tanks to ensure that the ship remained stable and said there was minimal risk of spillage during the pumping operation.

Environment Minister Corrado Clini meanwhile said that the environmental risk has been "our nightmare."

"The vessel has reservoirs full of fuel, it is a heavy diesel which could sink down to the seabed, that would be a disaster," he said.

In a worst-case scenario, the fuel could "leak into the sea, contaminating an exceptional coastline and affecting marine and bird life," he warned.

"We are ready to intervene if there is a spill," Clini said. "As soon as possible, the fuel will be removed from the vessel. But we have to take into account the precarious state of the ship."