The South Pacific region of Bougainville has voted in a referendum in favour of gaining independence from Papua New Guinea.

There were cheers when Bougainville Referendum Commission chairman Bertie Ahern announced the result in a public hall in the semi-autonomous province.

However, the referendum is non-binding, and independence would then need to be negotiated between leaders from Bougainville and Papua New Guinea.

The final say would then go to MPs in the Papua New Guinea parliament.

The Upe members vote at a men-only voting booth in the Bougainville referendum in Teau, Bougainville, Papua New Guinea
The Upe members vote at a men-only voting booth in the Bougainville referendum in Teau, Bougainville, Papua New Guinea (Jeremy Miller, Bougainville Referendum Commission via AP)

Around 85% of eligible voters cast more than 181,000 ballots in two weeks of voting.

The referendum is a key part of a 2001 peace agreement that ended a civil war in which at least 15,000 people died in the cluster of islands to the east of the Papua New Guinea mainland.

The violence in Bougainville began in the late 1980s, triggered by conflict over an enormous opencast copper mine at Panguna.

The mine was a huge export earner for Papua New Guinea, but many in Bougainville felt they received no benefit and resented the pollution and disruption of their traditional way of living.

The mine has remained shut since the conflict. Some believe it could provide a revenue source for Bougainville should it become independent.

The process of becoming a separate nation could take years to achieve.

Gianluca Rampolla, the United Nations co-ordinator in Papua New Guinea, congratulated national and provincial governments on the “inclusive and peaceful conduct” of the referendum.

“There are ways to go, and like all paths it may be neither smooth nor straight, but the United Nations will continue to be there as the two governments map their future, together,” he said.

David Sharma, an Australian government legislator who once lived in Bougainville as a diplomat and helped draft the 2001 peace agreement, said Australia would keep a close eye on developments for its nearest neighbours.

“I’m pleased that the Bougainvilleans have expressed their view in such a clear way, but I would sound a note of caution that Bougainville is an island of about 200,000 people and countries of that sort of population often struggle to take on all the full attributes of a sovereign state,” he said.

“How this plays out will be a concern. I think it is a time we need to tread cautiously and watch closely and do what we can to make sure the situation remains as calm as possible.”