UP to 70 people remain unaccounted for after a cruise ship carrying more than 4000 people ran aground and keeled over off the Italian coast, killing at least three people.

"There are three certified dead," local official Guiseppe Linardi said, correcting an earlier report that six people had died in the incident. Mr Linardi said that difficulties in the rescue operation had led to confusion over the toll.

Mr Linardi later said that as many as 70 people were missing, although the passengers could be safe on land.

"We have found 4165 [out of 4234], which is a difference of about 70 people," Linardi said. He said a door-to-door search was underway on the island of Giglio.

Teams of police divers continue to search the waters around the ship, working to establish whether any passengers were trapped.

The captain of the Costa Concordia is currently being questioned by port authorities, according to the Il Tirreno newspaper.

No Australians are believed to be among the dead.

Department of Foreign Affairs and Trade (DFAT) officials have so far made contact with 12 Australians who were on board the ship and who were uninjured, a DFAT spokeswoman said.

Officials remain at the scene where over 4000 people were evacuated.

"They are liaising with the shipping company and going through passenger lists,'' the spokeswoman said.

"We are not aware at this stage of any Australians being killed.''

The 290-metre Costa Concordia was on a trip around the Mediterranean when it hit a reef near the island of Giglio off Italy's Tuscan coast about 8pm local time Friday, sparking a massive overnight rescue operation.

"There were scenes of panic like on the Titanic. We ran aground on rocks near the Isola del Giglio. I don't know how this could happen. The captain is crazy," passenger Mara Parmegiani was quoted as saying by AFP.

Some of the ship's passengers jumped into the icy waters.

media_camera The luxury cruise ship Costa Concordia leans after it ran aground off the coast of Isola del Giglio island, Italy, gashing open the hull and forcing some 4,200 people aboard to evacuate aboard lifeboats to the nearby Isola del Giglio island, early Saturday, Jan. 14, 2012. About 1,000 Italian passengers were onboard, as well as more than 500 Germans, about 160 French and about 1,000 crew members. (AP Photo/Giorgio Fanciulli, Giglionews.it)

Rescuers surround the luxury cruise ship Costa Concordia after it ran aground off the coast of Isola del Giglio island, Italy.

One of the victims was a man aged in his 70s who was thought to have died of a heart attack caused by the shock of the cold water.

Italy's ANSA news agency reported that the Italian coastguard had recovered three bodies from the water, while other reports suggested more than 30 people had been injured.

Early today, most of the 3200 passengers and 1000 crew members had been evacuated, but some remained on board and were still to be airlifted off the listing ship.

The British foreign office said 24 Britons were on board the ship, adding that it was not aware of any injuries or fatalities among British passengers.

The 1500-cabin cruise ship had set off from the Civitavecchia port near Rome just two hours before the incident.

media_camera A file shot of the Costa Concordia cruising the Mediterranean.

A file picture of the Costa Concordia.

"We think this [incident] happened as a result of sailing too close to an obstacle like a reef," said a coastguard official, who confirmed there was a 30-metre hole in the ship's hull.

A statement from the Costa Crociera company, which owns the cruise ship, noted, "The slope, which gradually took over the ship, made the evacuation extremely difficult."

"Right now all our efforts are concentrated in the last emergency operations, as well as offering assistance to guests and crew who were aboard the ship, to bring them back home as soon as possible," it added.

The mayor on the island of Giglio - about 25km off Italy's central west coast - said officials were finding accommodation for the rescued passengers, including pregnant women and children.

The cruise ship boasts 58 suites with balconies, five restaurants, 13 bars, five Jacuzzis and four swimming pools.

Originally published as Dozens missing after cruise ship crash