SYDNEY (Reuters) -- An independence referendum for the Pacific island of Bougainville has been delayed by four months to October 17, leaders of the island and Papua New Guinea said on Friday.
Under a peace agreement signed after a nine-year civil war with the Papua New Guinea (PNG) mainland ended in 1998, Bougainville has until mid-2020 to hold the referendum, which had been scheduled for June.
The conflict was largely about how profits from a giant copper mine, Panguna, should be shared, and it forced resources giant Rio Tinto to abandon the mine.
At the time, the mine was the largest source of export revenue for Papua New Guinea and comprised about 7 percent of global copper production.
"The referendum on Bougainville's long-term political future will be held on 17 October 2019," PNG Prime Minister Peter O'Neill and Bougainville President John Momis said in a joint statement.
Three years ago the two leaders had set June 15 as voting day, but that was an "impossible" deadline because voter registration was underfunded and behind schedule, Bertie Ahern told the Australian Broadcasting Corp on Thursday.
Ahern leads the Referendum Commission overseeing the vote.
O'Neill and Momis said 10 million kina ($3 million) was available to fund the vote, with a further 10 million kina promised next week.
The conflict between Bougainville's rebel guerrilla army and Papua New Guinea forces left as many as 20,000 dead over the following decade, the worst conflict in the Oceania region since the Second World War.
Rio Tinto divested its stake in the shuttered mine's operator, Bougainville Copper Ltd, in 2016.
The outcome of the referendum, which analysts expect to support independence, is then subject to ratification by PNG's parliament. O'Neill and Momis have agreed to meet again in August to discuss arrangements should it succeed.