* Minister says risk of environmental disaster high
* Environmentalists says routes should be better regulated
* Ship carrying highly polluting "heavy fuel"
* Minister says state of emergency will be declared, freeing funds
By Philip Pullella
ROME, Jan 16 (Reuters) - As the Costa Concordia shifted dangerously on Monday, Italy's environment minister raised the prospect of an environmental disaster if the 2,300 tonnes of fuel on the half-submerged cruise ship leaks.
The ship's fuel tanks were full, having just left the port of Civitavecchia, north of Rome, for a week-long Mediterranean cruise, when it ran aground on Friday.
Rescue workers have recovered six bodies from the vessel and officials say 16 of the 4,200 passengers and crew are missing.
The area where the ship capsized, off the island of Giglio, is a natural maritime park noted for its pristine waters, varied marine life and coral. It is known as an excellent diving site.
"The environmental risk for the island of Giglio is very, very high," Environment Minister Corrado Clini told reporters. "The aim is to prevent the fuel leaking out of the ship. We are working to avoid this. It is urgent and time is running out."
Clini later told reporters in Livorno, up the Tuscan coast, that the cabinet would call a state of emergency. This would free up funds to prevent an environmental disaster or to deal with one.
The 290-metre-long ship is resting on an undersea ledge in 15-20 metres of water but salvage workers fear it could slip down the slope, which falls away sharply into much deeper water.
The ship shifted on its rocky ledge in worsening weather on Monday but after a brief suspension, rescue efforts resumed.
"We are now in the emergency phase of trying to prevent pollution," said Pier Luigi Foschi, chairman and CEO of the ship's owners Costa Cruises, who said the disaster was due to "human error" by the captain.
The ship is carrying heavy fuel, or bunker fuel. Because of its density, it is harder to pump out unless it is heated or diluted.
Clini said some liquid was leaking from the ship but it was not clear if it was fuel. A protective barrier was being put in place just in case.
Environmental groups have for years been asking that huge ships be banned from coming too close to the Tuscan archipelago, made up of the islands of Giglio, Montecristo, Pianosa, Elba, Capraia and Gorgona.
"These monstrous floating cities pollute the scenery with their very presence and the rivers, seas and cities where they stop with the refuse that they produce," said Alessandra Motola Molfino, national president of Italy's national conservation group, Italia Nostra (Our Italy).
"The disaster of the Costa Concordia unfortunately proves the insubstantiality of the type of tourism that exploits and tramples on Italy's beauty and cultural heritage and does not produce any growth or wellbeing," she told Reuters.
Clini said keeping large ships away from environmentally sensitive areas was "common sense" as Italy's natural beauty was "a fundamental resource" for the tourist industry.
Salvage companies are in place to try to remove the fuel after surrounding the vessel with a floating barrier. Dutch maritime services company SMIT has been asked by the ship's owner and insurer to pump out oil and clean it up if it started leaking.
A salvage expert on Giglio, who asked not to be named, said the ship was "definitely moving". He said it appeared to be held firm by points of rock which had pierced the hull, but with the rougher sea there was a risk it could break free, which he said would be "a big problem".
Foschi said the plan would be to remove the fuel then raise the ship with balloons and tow it away from shore. If that fails, he said he could not exclude that the ship would have to be cut into pieces.