The President of the Autonomous Bougainville Government has accused the Papua New Guinea Government of endangering the Bougainville peace agreement and lying about its dealings with mining giant Rio Tinto.

The company announced on June 30 that it was giving up its share of Bougainville Copper Limited, the company which ran the Panguna Mine that triggered 10 years of armed conflict known as the Bougainville Crisis.

Rio Tinto is giving 68 per cent of its BCL shareholding to the Autonomous Bougainville Government, but is adding the remaining 32 per cent to the PNG National Government's existing minority shareholding.

The deal will give an equal amount (36.4 per cent) of the majority shareholding to both the PNG and Bougainville Governments, and ignores the key demand of Bougainville's Government for a controlling interest in the mine.

Bougainville President John Momis says PNG Prime Minister Peter O'Neill told him on July 2 he had not discussed the share divestment with Rio Tinto and had not met with company executives.

But a notice to the Australian Stock Exchange shows a subsidiary of PNG Government company Petromin PNG Holdings Limited accepted the share transfer on June 30, the morning after Rio Tinto told the Bougainville Government of its decision.

Mr Momis said that directly contradicted what Mr O'Neill had said.

"Our lawyer checked the stock exchange in Sydney and found out in fact the Government had accepted 17 per cent of the shares that was offered to them, contrary to what the Prime Minister had assured me," he said.

"So it's duplicitous, he was telling me one thing and in the same breath the Government was doing something else."

The PNG Government is yet to respond to the ABC's questions about the share transfer or the Bougainville Government's statements.

Governments 'must adhere' to peace agreement

Mr Momis said the PNG Government could retain its original minority shareholding, but he wants it to transfer the extra shares from Rio Tinto to the Bougainville Government so it will have a controlling interest in the company.

Bougainville has passed a new Mining Act which could prevent BCL from ever exploiting the remaining gold and copper at Panguna Mine, but the company holds the resource data for the site.

The future of the Panguna Mine remains the most sensitive issue in Bougainville, which is preparing for an independence referendum in 2019.

Mr Momis said the PNG Government was risking the Bougainville peace agreement by hiding its dealings with Rio Tinto.

"The peace agreement is the benchmark that both governments must adhere to and the peace agreement rejects the kind of behaviour and action that the national government has embarked upon in the recent times," he said.

Mr Momis said he was writing to the Prime Minister to seek another urgent meeting and was recalling the Bougainville Parliament to discuss the issue.