One will be Prime Minister on Monday. Here's what you need to know about the three contenders for the top job.
Name: Simon William (Bill) English
Former profession: Farmer, policy analyst for Treasury. Entered Parliament in 1990.
Ministerial portfolios held: Finance, Housing New Zealand Corporation, Deputy Prime Minister. Long-standing MP for Clutha-Southland, although now a list MP.
Political leaning: Conservative. Anti-abortion, anti-euthanasia, voted against the Marriage Amendment Bill.
Best known for: Budgets, being John Key's right-hand man and his spectacular 2002 election defeat against Labour's Helen Clark (he was briefly National's leader from 2001 to 2002).
Scandal and controversy: He paid back some of his ministerial housing allowance in 2009 after it emerged he claimed nearly $1000 per week to live in his family home in Wellington, including for power and cleaning.
Private life: A Catholic, he is married to a GP and has six children.
On his bid to be PM: "I can focus on some of the intricacies of complicated issues."
Name: Judith Anne Collins
Former profession: Lawyer. Entered Parliament in 2002.
Ministerial portfolios held: Justice, ACC, Ethnic Affairs, Corrections, Police. MP for Papakura.
Political leaning: On the conservative right of the National caucus.
Best known for: Her hard-line on boy racers earned her the name "Crusher Collins".
Scandal and controversy:
- Dirty Politics 2014: She was accused of leaking information to her friend and right-wing blogger Cameron Slater in the book Dirty Politics. She resigned from Cabinet after allegations she tried to undermine the Serious Fraud Office director. An inquiry cleared her of wrongdoing.
- Oravida 2014: She visited the Shanghai offices of Oravida, of which her husband is a director, while on a taxpayer-funded trip. The company used her photo as a product endorsement.
- Wetlands comments 2014: It emerged swamp kauri had been stockpiled in Northland under the name Oravida Kauri, another business linked to Oravida and Ms Collins' husband. She outraged environmentalists by telling a reporter she did not care, saying, "Am I the Minister of Wetlands?"
Private life: Grew up on a Matamata farm. She is married to businessman David Wong-Tung and they have one son.
On her bid to be PM: "It's about who can deliver a National-led government, do whatever deals are needed."
Name: Dr Jonathan David Coleman
Former profession: Medical doctor, health consultant. Entered Parliament in 2005.
Ministerial portfolios held: Immigration, Defence, State Services, Sport and Recreation, Health. MP for Northcote.
Political leaning: Conservative. Voted against the Marriage Amendment Bill.
Best known for: Smoking a cigar in a British American Tobacco corporate box at a U2 concert, health funding troubles.
Scandal and controversy:
- The U2 concert in 2006. He was National's associate health spokesman at the time.
- Accused of bullying the Canterbury District Health Board over funding issues, on the back of sacking the Southern District Health Board in 2015.
- Dunedin Hospital patients complained about the food they were served. Mr Coleman ate a hospital meal (behind closed doors) and claimed to love it.
Private life: Grew up in Auckland, attending Auckland Grammar. Married with two children. Has a holiday home in Omaha, the same beach where outgoing Prime Minister John Key has a house.
On his bid to be PM: "We've got to build on the excellent platform that we've been working off for the last eight years."