A Bougainville landowners' group and miner RTG have hit back after more criticism from President John Momis.
Both RTG and the government of the autonomous Papua New Guinea region are seeking the right to re-open the controversial Panguna copper and gold mine.
The clash comes as Bougainville prepares for a referendum on independence from PNG.
Mr Momis wants to open the mine to help fund the referendum process and is planning changes to the Mining Law, which will give a new company almost complete control of the mining of minerals in Bougainville.
He claimed RTG had lied in saying the measure denies the rights of the Osikaiang landowners at the site of the mine.
But the landowners and Osikaiang say the government's plan to link with a newly established, tax haven registered company, Caballus, which would facilitate the mining, is a pipe dream.
Osikaiang has listed 16 points challenging the government's move.
These include vague promises over landowners retaining ownership of the minerals, claims the billions needed to develop the mine can be generated by the government itself and they question whether an untried miner, Australian Jeff McGlinn, has the acumen to run a major mining company.