The Bougainville landowner group, Special Mining Lease Osikaiyang Landowners' Association or SMLOL, has rejected claims by another group claiming rights around the Panguna mine.
There have been plans to re-start mining as Bougainvilleans contemplate life after the referendum on independence from Papua New Guinea.
A company called the Panguna Development Company has questioned the bona fides of SMLOL to say they represent the landowners at the site of the mine.
But SMLOL said it has the backing of the vast majority of blockholders, that its authority is recognised by the National Court and that its registered office is at the building housing the Bougainville Department of Mining.
SMLOL also said the Panguna Development Company was established just a few months ago by a rival for the re-opening of the Panguna mine, Bougainville Copper Ltd.
A SMLOL spokesman Philip Miriori said Panguna Development Company has just one listed shareholder, Eric Takapau, who he said had since passed away.