The president of the autonomous Bougainville government has accused an Australian-linked mining company of lying to the Australian Securities Exchange over its plans to reopen one of the world’s largest copper mines.

In a scathing statement, John Momis, the president of the autonomous Bougainville region, accused the Australian-linked RTG Mining of “lies and deceptions” and said his government “will not rest until all RTG and their executives are banned for life from Bougainville and Papua New Guinea”.

Momis was referring to a statement issued by RTG Mining to the ASX on Tuesday in which the company sought to clarify recent press reports, which have alleged that RTG staff are banned from entering Papua New Guinea.

In December, after the results of a referendum that saw almost 98% of Bougainvilleans vote in favour of independence from PNG, Momis issued a warning banning people affiliated with certain foreign mining companies, including six from RTG and one from Kalia Group, from entering Bougainville. Momis said they were creating “disharmony” in the region and that he had sought the assistance of the PNG prime minister and office of immigration and border security to assist with keeping them out of Bougainville.

However, RTG clarified in its statement to the ASX that its executives were “not banned from travel to Papua New Guinea” and emphasised that “the national government currently [have] constitutional authority over border control for the country”.

RTG is seeking to secure an exploration licence at the Panguna mine in Bougainville. The Panguna mine was at the heart of the brutal civil war in the region that saw an estimated 20,000 people killed between 1988 and 1997. The mine, which once provided 45% of Papua New Guinea’s export income, has been mothballed since the conflict began, but there has been talk about reopening it.

Among the companies in talks about resuming mining in Bougainville are RTG, which is listed on the Canadian and Australian stock exchanges, ASX-listed Kalia, Bougainville Copper Limited, a former subsidiary of Rio Tinto that ran the Panguna mine in the 1970s and 1980s, and Caballus Mining.

Andrew “Twiggy” Forrest has also expressed interest in mining in Bougainville, with the Sydney Morning Herald reporting that representatives of his mining company, Fortescue, travelled there in 2019 to explore “potential opportunities”.

There are disputes over land rights at the Panguna mine site, but RTG is the joint venture partner of the Special Mining Lease Osikaiyang Landowners Association (SMLOLA). RTG wrote in their statement to the ASX that the members of the SMLOLA “are the customary landowners who own the minerals at the Panguna Mine under the Bougainville Mining Act”.

However, Momis said the SMLOLA was established under an old system and that the autonomous Bougainville government considered its claims over the mine “illegal, null and void”.

There are concerns that disputes over land rights at the mine site might reignite tensions in the region. The Bougainville government enacted an indefinite moratorium on renewing the licence of BCL, a controversial mining company, in January 2018 over fears it could reignite violent civil conflict. However, since then, the government has shown signs that it was in favour of restarting mining in the region.

Despite voting for independence from PNG, the question of how an independent Bougainville would support itself hangs over the vote, with some experts saying it is impossible for Bougainville to become financially independent without a strong mining industry and that it would take much longer for other mining projects to be established and become profitable than it would take to reopen Panguna.

The autonomous Bougainville government and RTG Mining were contacted for comment.