Two Britons are believed to have been aboard a stricken ferry that caught fire off the Greek island of Corfu, according to the UK's ambassador to Greece.

Greek and Italian rescue helicopters and vessels have struggled to reach the ferry, battered by 55 mph winds that sent it up toward the strait between Italy and Albania.

Nearby, merchant ships lined up to form a barrier to protect the ferry and facilitate rescue, said Italian Navy Captain Riccardo Rizzotto.

The fire broke out on the car deck of the Italian-flagged Norman Atlantic, travelling from the Greek port of Patras to Ancona, Italy, with 422 passengers and 56 crew on board.

"We understand from the passenger manifest that 2 British nationals are believed to be on board," British Ambassador to Greece John Kittmer said on Twitter.

"We are in close contact with the Greek authorities and are urgently seeking more information ...

"We understand that the Greek authorities are working with the Italians, who are leading the rescue effort."

One person has died while attempting to escape from the blazing ferry stranded in the Adriatic Sea, and another has been injured, according to an Italian Coast Guard official.

There have been 117 people transported to safety - eight airlifted to southern Italy and the rest taken to nearby ships, said Greek Merchant Marine spokesman Nikos Lagadianos.

But high seas have hampered rescue efforts, and at one point strong winds forced helicopters to be grounded, authorities said.

British woman Dotty Channing-Williams said her son Nicholas was aboard the Norman Atlantic with his fiancee Regina, and that she had spoken to him by telephone since the fire broke out, but that she had since lost contact with him.

"People in Greece are saying that their communications have been cut off, so as not to hamper rescue operations which I can fully understand," she told Sky News.

"They're keeping me updated via the news coming over the Greek television. But nevertheless it is very, very worrying and very scary.

"So I just hope that they will be able to get everybody off there as soon as possible.

She said she had spoken to officials at the Home Office but had not had any direct contact with those in charge of the rescue operation.

When she spoke to her son he had been standing on the ferry's top deck for seven hours "in the rain and thunder and lightning".