Greek officials have confirmed that the death toll following the sinking of a ferry off the Aegean island of Paros has risen to 62 with 29 people still missing.

It said 443 people had been rescued or accounted for after the ferry Express Samina ran aground and sank late on Tuesday in gale-force conditions.

British Royal Naval vessels which were called away from a nearby military exercise, helped in the search for survivors.

They launched three helicopters and rescued at least 12 people from rocks and took them aboard HMS Invincible for treatment.

However, the ships are now withdrawing from the scene as the chance of finding further survivors diminishes.

Earlier, the Greek Merchant Marine Ministry had said 510 passengers and crew were on the ferry when it ran aground.

It was not known why the Coastguard and Merchant Marine Ministry had different passenger totals.

Coastguard vessels, trawlers, pleasure craft and fishing boats combed the seas for survivors from the Express Samina.

The ferry went down after hitting a large rocky outcropping about two miles off the popular resort island.

Coastguard officials were baffled as to why the 450-foot, 4,407-tonnes Express Samina hit the Portes islet, which is marked on maritime charts and has a navigation light.

"You have to be blind not to see it," Coastguard Chief Andreas Sirigos said.

The captain of another ferry, Theoharis Tsoukalas, said he made the same run almost every day and could not remember "any other ship ever hitting there."

Passengers and crew aboard said the Express Samina sank within 45 minutes of hitting the islet.

Chief Sirigos said the Coast Guard was also investigating why it took the crew nearly 20 minutes to inform the coast guard that the ship was sinking.

A crew member interviewed by telephone said there was an orderly evacuation.

"There was time enough for all of us to get out, including the people in the cabins. We got them all out," Stephanos Papadopoulos, a ship's officer, told Athens' Antenna television.

But passengers reported panic as the ship began listing to the right after hitting the rocks.

"The ship fell apart as it sank. There were people hanging from the railings. Children were crying and old people were screaming," said survivor Zoe Kolida.

"I jumped in and looked back after about 50 metres and the ship was gone."

Another survivor, engineer Stamatis Delavinias, said the collision "was very strong.

"I thought of the Titanic. The boat sank in about half an hour. There were old women and others who were afraid to jump in the sea."

"Lots of people jumped into the sea. I jumped into the sea. I knew the vessel was going to sink once it started listing. I could hear people screaming in the distance," passenger Andreas Spanos said on television.

Officials said hundreds of people were taken to local hospitals on Paros, while others were put up in hotels.

Many of the less seriously injured were being treated for cuts, bruises and hypothermia.

Doctors from all neighbouring islands were called to Paros and a special medical team flown in from Athens as a flotilla of rescue boats combed the area for survivors.

The Greek Merchant Marine Ministry said a Greek coastguard official had died of a heart attack in the rescue operation.