A Papua New Guinea opposition MP Sam Basil has warned about the prime minister Peter O'Neill's interest in the Panguna mine in Bougainville.
Mr O'Neill last month met with the president of the autonomous Bougainville region, John Momis, over a reported government proposal to purchase 53% of Rio Tinto's shares in Bougainville Copper Limited.
Mr Momis, whose administration has been in recent discussions with BCL about a possible re-opening of the mine, rejected the proposal.
The prime minister has since denied that the government is interested in buying in on Panguna.
But Mr Basil says Mr O'Neill's latest move to appoint himself Minister for Bougainville Affairs is ominous.
"With his actions, in terms of dealing with other mines - Tolukuma and Ok Tedi - I think the people of Bougainville should be very wary of the prime minister's actions, and they should be very careful on how they allow the prime minister to deal with their mine. So we should be very careful with Mr Peter O'Neill. He has lied to us many times."