Four of the nine Bulgarians on board the Norman Atlantic, an Italian-flagged ferry which has been ablaze since Sunday morning, have been rescued, officials say.

Betina Zhoteva, a spokesperson for the Ministry of Foreign Affairs, has told the Bulgarian National Television that R. Todorova, S. Bozhilova, G. Haytov and K. Estov are in a stable condition.

As many as 216 people, of the 422 passengers and 56 crew, were on the Norman Atlantic when a fire started on board while the vessel was off Corfu, Greece.

Reportedly, one Greek has died and seven have been injured.

There were nine Bulgarians on the ferry at the time of the incident.

A number of vessels tried but failed to provide assistance in the rescue operation which has been ongoing for hours under extremely severe weather conditions.

Passengers are being rescued with helicopters, but these allow for only a few people at a time to be saved.

The 26,900-tonne, roll-on roll-off ferry Norman Atlantic carried nearly 500 passengers and crew from the Greek port of Patras to Ancona in Italy when it sent a distress signal.

A document cited by Greek daily Kathimerini shows some of the ferry's safety features were either malfunctioning or missing while it was undergoing an inspection at the port of Patra on December 19.