The Victorian-era Fort Delimara is being given an extensive clean-up after years during which it was used as a pig farm.
The culture ministry said consolidation works are also being carried out, improving accessibility to its most important parts.
The minister, Owen Bonnici, toured the site on Tuesday and was shown around by Heritage Malta CEO Noel Zammit
Heritage Malta said works have been underway for the past year, also involving other organisations. The works included a clean-up of the underground areas and the courtyard.
Structures which had nothing to do with the fort were dismantled. A new water and electricity system has been installed.
Fort Delimara was built between 1876 and 1878 to protect Marsaxlokk harbour.
It still features four ancient 38-ton guns, the only surviving examples of their type in the world.
The fort remained in use until 1956 and was used as a pig farm for 25 years. Heritage Malta took possession in 2005.