Archaeologists working for the institute for research and development in New Caledonia have discovered a historic fort in the Loyalty islands.
Officials in the north of Maré have found cut blocks of coral more than three metres high which make up a fort of more than two square kilometres in area.
The discovery is expected to shed light on ancient Polynesian settlement in what is now largely a Melanesian island.
The territorial institute for research and development say it's difficult not to link the fort with similar buildings in western Polynesia.
The institute says fortifications in some islands in the area are linked to raids by warriors from Tonga and Samoa.
Traditional knowledge on Maré has it that such invasions occurred four hundred years ago.