Migrants scramble on a capsizing fishing vessel before a rescue operation by Italian Navy ships off the Libyan coast. Five people died and 562 were rescued. Reuters

A dramatic image captures the moment a heavily overcrowded boat overturned in a shipwreck off Libya that left at least five people dead.

The fishing vessel, its deck heaving with people, tipped over after the migrants rushed to one side on seeing a rescue ship - an all too frequent mistake that has led to many disasters in the Mediterranean.

The image was part of a series released by the Italian Navy on Wednesday.

The migrants, many of them men, and some already wearing life jackets as a precaution, were pictured as they clung to the boat's rails, to each other, or fell like stones into the sea.

Some are seen hanging on to the starboard side of the vessel by their fingertips as it rolls, while others try to balance on the edge.

Pictures taken seconds later show the churning waters around the boat full of people trying to get away from the overturned vessel, which begins to sink with four people perched on the upturned hull.

The Navy said a patrol boat spotted "a boat in precarious conditions off the coast of Libya with numerous migrants aboard" but the fishing trawler overturned shortly afterward "due to overcrowding".

Life rafts and jackets were thrown to those in the water, while another Navy ship in the area sent a helicopter and rescue boats. The Navy said 562 people were pulled to safety and the operation ended without finding any further survivors or victims.

The migrants had sounded the alarm by calling for help using a satellite phone about 33 kilometers off Libya.

It is not the first time a boat making the perilous journey across the Mediterranean has overturned because of sudden movement onboard when help is in sight.

In August, a Palestinian survivor of such a shipwreck described the moment the boat rolled as "like being flung from a catapult. I could only see heads, all around, amid the waves, everyone pushing down on everyone else to try to stay afloat".