An extremely rare Roman bronze rostrum used for ramming enemy ships - which may have been used in the last great naval battle in the First Punic War - has been found off the northwest coast of Sicily.

The rostrum, a single piece of fused bronze, would have been positioned at the ship's bow and was smashed with force into enemy boats in order to sink them fast.

Divers working for Sicily's maritime affairs department recovered the rostrum near the Egadi Islands in water 70 metres deep with the aid of remotely operated vehicles (ROVs).

''At the moment this is the fifth extant rostrum in the world,'' said department head Sebastiano Tusa, adding that Sicily is the only region to possess two.

The second rostrum was recovered by art police in 2004 after fishermen discovered it in water near Trapani, not far from the Egadi Islands.

The Trapani rostrum is now conserved in the city's Pepoli Museum.

Tusa said that the Egadi rostrum confirms his theory that a battle took place north-east of the island of Levanzo between fleets from Rome and its great enemy, Carthage, during the Battle of the Egadi in 241 BC.

The battle, won by the Romans, ended the First Punic War and saw the Carthaginians hand control of Sicily to the Roman Empire.

The word rostrum was later used for the main speaking platform in the Roman Forum. This was because it was decorated with the prows of captured ships.