Under a peace agreement signed after a civil war with the PNG mainland, Bougainville has a five-year window, beginning in June this year, during which it must hold the referendum.
Whoever is elected in this month’s ballot will negotiate with PNG the exact date of the referendum and the wording of the question.
“I have been asking people to go to the polls, cast their votes and elect good leaders,” the acting Bougainville Electoral Commissioner George Manu said.
“This government will be the government that will be deciding on the future of all the people of Bougainville.”
It is the first time Bougainville has run its own elections, rather than being led by the PNG national government.
At a pre-poll briefing on Sunday, Mr Manu thanked the United Nations, Australia and New Zealand for their help in preparing for the election.
Bougainville’s 172,797 enrolled voters will elect a president and 39 members of the House of Representatives, with reserved seats for women and ex-combatants.
Conflict over the Australian-owned Panguna mine in 1989 turned into a civil war which smouldered during the 1990s, although peace has returned to the mineral-rich island.
With media virtually non-existent outside the biggest towns of Buka and Arawa, campaigning has been a village-to-village affair of noisy stump speech rallies.
There will be a week of polling and a further week allowed for bad weather or other delays, followed by a week of counting, with a similar contingency week.
A result is expected on June 8.
There are nine candidates for president.
The incumbent, Dr John Momis, is widely seen as the favourite but the fact 20,000 new voters have been added to the electoral roll and many thousands of illegitimate voters taken off, means this is a race any of the top contenders could win.
Dr Momis is one of the founding fathers of independent PNG and is offering voters a steady hand at the helm as Bougainville enters this crucial period.
He is running with the slogan “For the Future of Bougainville” and is the most measured on the question of independence.
Surprisingly, several ex-combatant groups have thrown their support behind the former Catholic priest.
Sam Akoitai is a former mining minister in the national PNG government and former central Bougainville MP who ran the most sophisticated and well-funded campaign over the past few weeks.
He is a former fighter, advocates strongly for independence and wants to see a diversified economy, including a revitalisation of the plantations that have been left to grow wild since “the crisis”.
Akoitai is telling voters only he can navigate Port Moresby’s corridors of power to deliver a referendum that benefits Bougainville, but his time spent away from the island also works against him in the eyes of some voters.
Another charismatic ex-combatant is Ishmael Toroama.
Campaigning with the slogan “We Are Ready”, Toroama argues that Bougainville has already been going it alone for many years and a referendum will merely formalise that independence.
In 2012, he narrowly lost the race for a Bougainville regional MP seat, showing he can muster the numbers when it counts.
Sam Kauona is a similarly well-known former leader of the Bougainville Revolutionary Army who has wide support in the central region of the island.
He is also the candidate who has campaigned the least.
It is unclear whether Kaona and Toroama will split a bloc of voters who want independence delivered by a local ex-combatant or whether the limited preferential voting (numbered choices 1,2 and 3) can deliver power to one of them.
Nick Peniai, former Speaker of Bougainville’s House of Representatives who ran for president in the 2010 elections, is also considered a chance.
A total of 333 candidates are running for the 39 available MP positions.
Most of these are single constituency seats, but Bougainville’s electoral system reserves three seats for women and three seats for ex-combatants.
There is one reserved seat for each of the three regions of the island – North, Central and South.
Bougainville’s culture is based on matrilineal land ownership but men still hold most of the power. As well as the women contesting for reserved seats, there has been a small but encouraging increase in the number of women who nominated for an open seat.
Women still make up less than four per cent of nominees, but it is seen as a shift in the right direction.
They are some quirky showdowns amongst the open MP seats.
Two brothers are facing off for the seat of Tonsu on Buka island and a married couple have both nominated, but for different seats.
Three Catholic priests are in the running for House of Representative seats – including Father Joseph Nabui –who was the first serving priest to gain office in Bougainville in a by-election in 2013.
Four Australian MPs will be among the 75 domestic observers and 50 international observers monitoring the poll.