The Italian Air Force is rescuing hundreds of migrants stranded on a cargo ship apparently abandoned in rough seas by smugglers in the Mediterranean.

The Air Force said late Thursday night it sent a helicopter from an air base in southern Italy to help the Ezadeen, a Sierra-Leone-flagged vessel, so Coast Guard officials can be lowered to secure the ship and doctors can also come aboard.

Coast Guard Cmdr. Filippo Marini said early today that a migrant had called for help saying: "'we're without crew, we're heading toward the Italian coast and we have no one to steer.'"

Exactly how many were aboard was unclear, but the ANSA news agency said there could be as many as 450. The Ezadeen was some 64 kilometres off Italy's southeastern tip.