The president of the Autonomous Bougainville Government (ABG) says mining companies must win the trust of landowners if they want to operate the Panguna mine.
Last month, President John Momis placed an indefinite moratorium on mining at Panguna after landowners opposed the return of miner Bougainville Copper Limited, or BCL.
The landowners said BCL would not take responsibility for the environmental and social impacts of its previous operation.
BCL ran Panguna until the outbreak of civil war in 1989 in which grievances caused by the mine were central to the 10 year conflict that cost over 20,000 lives.
Mr Momis said to avoid further conflict, Panguna could only be opened with the landowners' consent.
"Because of our concern that it might ignite another war, we decided, on the recommendation of the Bougainville Mining Council, to impose an indefinite moratorium on mining on Panguna," he said.
"The mine can recommence, but we have to ensure that whichever company gets the license must be acceptable to the people. In other words it must win the social license."
The vast Panguna copper and gold mine once generated nearly half of Papua New Guinea's annual export revenue.
In 2016, mining giant Rio Tinto transferred its controlling stake in BCL to both the PNG government and the ABG, winning support from Mr Momis for BCL to return to Panguna.
But opposition to BCL from the Special Mining Lease Osikaiyang Landowners Association was reiterated this week by its chair Philip Miriori, who said it was time for Bougainville to attract a mining partner that would respect the people and make sure they all benefit.
Australian mining company RTG claimed to have the landowners' backing last month when its chairman Michael Carrick told RNZ Pacific his company was a better option than BCL.
Mr Momis said it was not clear if an Australian company could provide landowners the same benefits as one partly owned by the ABG.
"That may be so but that is not the view of the people of Bougainville. We have a referendum coming up which is important for the ultimate determination of our future and we can't allow BCL's involvement in Panguna that may lead to bloodshed," he said.
"We can't open the mine in the face of such huge opposition from the people. According to our law, the landowners own the resource, not the government. Until companies win the social license from the landowners they are barking up the wrong tree."