The walls at Fort Ricasoli are being saved from collapse in a project estimated to cost Lm110,000.
The fort was badly damaged in 1807 when a gunpowder store exploded during a riot. A storm in 1921 also caused considerable damage, and the Second World War subsequently took its toll.
The British had attempted to restore the fort by resurfacing the walls with stone, but this has since become unstable.
The works were visited recently by Resources and Infrastructure Minister Francis Zammit Dimech.