Papua New Guinea's controversial prime minister Peter O'Neill has secured a second term after a troubled election process that took almost six weeks.

Key points: Peter O'Neill won the a parliamentary vote 60 to 46

Peter O'Neill won the a parliamentary vote 60 to 46 He will face an even larger Opposition in the new Parliament

He will face an even larger Opposition in the new Parliament Mr O'Neill said electoral processes will be reviewed after several controversies

Mr O'Neill mustered enough support on the floor of parliament — 60 votes to 46 — to secure the Prime Minister's post after several days of coalition negotiations.

The inaugural sitting was delayed twice; once when officials had to deal with two men who had been declared winners of the same seat, and again when parties opposed to Mr O'Neill demanded the clerk adjourn parliament and eject members whose declarations are disputed.

"It's unfortunate but you know in PNG sometimes you expect this," Mr O'Neill said.

"It's certainly not something we all wanted in parliament, but it was just a little bit of a circus created by our opposition."

The election has been widely criticised because thousands of voters were excluded and there were glaring abuses of the electoral process.

Mr O'Neill promised parliament that the issues would be addressed.

"Yes, there have been challenges in this election, but this has also been the most peaceful elections in many parts of our country," he said.

"There have been difficulties at the administrative and organisational level.

"This Government commits to a full review of electoral processes, that will provide an opportunity for all stakeholders to share their views."

O'Neill to face larger Opposition

Mr O'Neill still has to deal with an outstanding arrest warrant for corruption charges and now has a much larger Opposition in parliament.

He said he would heed the message from voters who ousted senior members of his party, including the Deputy Prime Minister, Speaker and Attorney-General.

Opposition members wanted parliament to adjourn, and for members whose declarations were disputed to be ejected. ( ABC News: Eric Tlozek )

"We've heard what the people have said in the elections, we've taken stock of it and we will do every bit to do it better," he said.

The two next biggest parties in the parliament, the National Alliance and Pangu Pati and a number of independents have promised to be a steadfast parliamentary Opposition.

National Alliance leader Patrick Pruaitch said the group had done their best to change the government.

"Unfortunately we don't have the numbers to muster to get into government but let me assure Papua New Guinea that you have already seen what it's like — a vibrant team who is ready to take on the government in terms of how to manage the country," he said.

"I can assure the rest of the country that we remain focused, we have seen your feeling, your mood, unfortunately we don't have the numbers to represent your mood.

"Every one of us has demonstrated that we are representing the true interests of our country."