The party has dropped from 12 MPs to nine following the election. Richard Prosser, Mahesh Bindra, Denis O'Rourke, Pita Paraone and Ria Bond are all now out of Parliament.
Media will be waiting at Parliament for Peters and his new caucus to arrive. They are:
Ron Mark
The party's deputy leader came from Labour but holds conservative views including on law and order. Mark was Labour's Selwyn candidate in 1993, later joining New Zealand First and working as an MP from 1996 until 2008.
He was elected Mayor of Carterton in the Wairarapa in 2010, and returned to Parliament for NZ First in 2014. He became deputy leader the following year after initiating a coup against Tracey Martin.
Passionate about recycling and known for his combative style around Parliament, Mark was raised as a ward of the state and later served in the army.
Tracey Martin
Elected to Parliament in 2011 and serving as deputy leader until 2015, Martin is the daughter of former party president Anne Martin. A strong advocate on education issues and is seen as aligning more closely with education unions and much of Labour's policy.
A former Rodney Local Board member, Martin has been strongly critical of National's core education policies including national standards. The architect of NZ First's tertiary education policy, which would give students free study so long as they stay in New Zealand and work the equivalent time of study. Labour has pledged to eventually introduce three years of free post-school study or training.
Fletcher Tabuteau
Is steeped in NZ First, having been a member for 22 years after his politically active parents were among the first supporters. His uncle, Tommy Gear, is close friends with Peters and worked as an NZ First staffer for many years.
Taught at Rotorua Boys' High School and later as programme leader for Waiariki Institute of Technology Business Management. Entered Parliament in 2014 and has led his party's opposition to the Trans-Pacific Partnership and is commerce spokesman.
Darroch Ball
The former biology and science teacher and army officer is based in Palmerston North and entered Parliament in 2014.
Ball is a solo father with two children, and has been a strong critic of the National Government over youth justice and employment. He's also held NZ First's research, science and technology, civil defence and consumer affairs portfolios.
Clayton Mitchell
The party's whip and a former Tauranga City councillor with a strong background in small business, having owned bars and an import business, and chairing Bay of Plenty Hospitality NZ. Entered Parliament in 2014.
His father, Bob Mitchell, was a campaign manager for National MP Anne Tolley, and the chairman of the party's Napier electorate. Mitchell's mother was a strong Labour supporter, and his grandfather a deputy leader of the New Zealand Communist Party.
Mark Patterson
A sheep and beef farmer from Lawrence and NZ First's candidate in Clutha Southland who was once a National Party supporter and unsuccessfully contested to be the party's Clutha-Southland candidate after Bill English went on the list. One of three new MPs.
Shane Jones
A high-profile recent recruit, Jones unsuccessfully stood in Whangarei for NZ First after a stint as Ambassador for Pacific Economic Development. He was an MP and minister in the previous Labour Government and contested for the party leadership in 2013, losing to David Cunliffe. A potential successor to Peters, rivalling Ron Mark.
Jenny Marcroft
A former newsreader and broadcaster who has worked with Tracey Martin and has been involved with Ngapuhi settlement talks. She contested the Tamaki seat for NZ First and has now entered Parliament on the party list.
