This follows 50 days of campaigning by the 25 candidates in the running for the island's top job.
Polls close on September 1 with counting starting the following day, with all votes expected to be counted by September 14.
Writs will be returned to the Governor-General on September 15 and the new ABG president expected to be sworn in the next day.
Two decades after combatants snapped arrows to signal the end of hostilities, there is anger among the younger generation that there has been little economic progress for the resources rich region.
"It has been wasted on mere politics, and there's nothing on the ground to show for it," Pajomile Minaka, a 37-year-old law student, told Reuters by telephone.
"In terms of bringing sustainable economic development there is nothing. Young people like me believe the government has failed the people."
Bougainville's 250,000 strong population has a median age of just 20, a demographic that is likely bad news for the ex-combatants among the open field of 25 candidates vying for the top political office.
Younger voters were likely to push for a fresh face, even though prominent figures from the conflict had the advantage of wide-spread name recognition, said Paul Barker, executive director of Port Moresby-based think-tank the Institute of National Affairs.
"There is a strong element of the lost generation missing out and wanting change," Barker said.
Bougainville descended into a decade-long conflict in 1988, triggered by a dispute over how the profits from the lucrative Panguna gold and copper mine should be shared and the environmental damage it had caused. As many as 20,000 died during the fighting between the region's rebel guerrilla army and PNG forces, and Panguna was closed.
Last year's non-binding independence poll was part of the peace process that ended the conflict, but competing claims over development rights to Panguna still hang over its future.
Bougainville Vice President Raymond Masono said Panguna should "play a major role in revitalising Bougainville's economy".
Younger voters, like Augustine Teboro, 30, said it was time to dispense with the "old view" that Bougainville's future relied on re-opening Panguna when it should be making use of its physical and natural beauty by cultivating its tourism, agriculture and fisheries industries.
"Our hope is that this generation will transform our society and not be a generation that will make the same mistakes of the past," said Teboro, who heads a Bougainville youth federation.
"We are looking for a civilian leader with integrity."
With no formal political polling and a diverse list of candidates to replace long-serving President John Momis, the election is considered an open race.
Among the old guard candidates are former president and combatant James Tanis and government-backed candidate Thomas Raivet. Other candidates include Fidelis Semoso, who served in the national PNG parliament, lawyer Paul Nerau and businessman and former sports administrator Peter Tsiamalili Junior. There are also two women candidates, health-care professional Ruby Mirinka and former Bougainville MP Magdalene Toroansi.
Polling is likely to be complicated by the first recorded cases of Covid-19 in Bougainville.
The coronavirus pandemic has also thrown a cloud over whether international observers will be able to attend. The United Nations said in a statement the Bougainville Electoral Commissioner had asked the PNG government to invite diplomatic missions in Port Moresby to observe the vote, Reuters reported.
"This election will determine the future political status of this emerging nation," Masono said. "The next government must consult with the national government on independence - nothing more, nothing less."