Bill English is now Prime Minister, after being elected leader of the National Party in a caucus vote this morning and being sworn in by the Governor-General. Paula Bennett has been confirmed as his deputy.
Talk is now turning to his Cabinet reshuffle, which Mr English says will happen before Christmas.
With the number one and two spots cemented, as well as Steven Joyce becoming Finance Minister, there will be an opportunity for change among the rest of the Cabinet.
Mr English has indicated there will be changes on the backbench, and it's thought some lowly-ranked ministers face an uncertain future.
On the chopping block are ministers outside Cabinet, including Craig Foss, Louise Upston, Jo Goodhew, and Nicky Wagner.
Inside Cabinet, the most likely to be demoted is Sam Lotu-Iiga who has struggled with the numerous portfolios he has held, mainly Corrections and the Serco saga.
3pm - The ceremony is over, and Bill English is now New Zealand's Prime Minister, with Paula Bennett as his deputy. The pair are now having something to eat and drink, with the gathered dignitaries.
Paula Bennett watches as Bill English becomes New Zealand's Prime Minister (Isobel Ewing / Newshub.)
2:55pm - Bill English has now appointed Paula Bennett Deputy Prime Minister, completing a transition of power that's taken exactly one week.
Ms Bennett sported a huge smile, thanking those present.
"Congratulations on your appointments," Dame Patsy Reddy told the pair.
Paula Bennett and Bill English (Isobel Ewing / Newshub.)
2:54pm - Dame Patsy Reddy has signed a document, confirming Bill English is now New Zealand's Prime Minister. She does so on behalf of the Crown. The room erupted in applause, while Mr English struggled to hold back a smile.
2:50pm - Dame Patsy Reddy, the Governer-General, has shaken hands with Bill English and Paula Bennett. The trio have now sat down to be sworn in as Prime Minister and Deputy Prime Minister.
2:45 - Formalities are about to get underway at Government House, to formally swear in Bill English and Paula Bennett as the country's new leaders.
In the meantime, Jenna Lynch reports on what John Key plans to do with his blind trust, now he's no longer the Prime Minister.
2:35pm - Australia's former Treasurer Joe Hockey says he's "very excited" Bill English will be New Zealand's Prime Minister.
He praised Mr English's way with money, saying he'd lost "much money" to him in bets on All Blacks games.
Meanwhile, Mr English has taken a call from present Australian Prime Minister Malcolm Turnbull.
2:10pm - Bill English won't stay in Premier House.
"We're happy in the house we're in."
He says he'll sort out who will live at the state-owned residence "at a later date".
"It's yet to be sorted out. I'm sure it's on the minds of every New Zealander."
He's promised it won't be sold.
2pm - A knighthood appears to be on the cards for John Key.
"I'm sure that at some time that'll be appropriate," Bill English said on Monday. "It's not as if he's never asked."
1:50pm - In case you missed it live, here's John Key's final press conference as Prime Minister.
1:46pm - With a quick "see you guys, bye-bye" the soon-to-be ex-Prime Minister got into a waiting car and left.
1:43pm - Mr Key doesn't think the party will swing further to the right under Bill English, regarding race relations. He took a potshot at Don Brash, and said Chris Finlayson has a done a great job looking after Treaty negotiations.
John Key answers questions at his final press conference as Prime Minister (Lloyd Burr/Newshub.)
And after saying Mr English has been a world-class Finance Minister, Mr Key abruptly ended the press conference and went outside, where hundreds - including his party's MPs - gathered to farewell him from the job.
1:40pm - Mr Key sees his leadership on the economy and shepherding the country through times of crisis as his two biggest successes.
And despite his popularity, he's looking forward to being "anonymous".
"I really love my engagement with the public. I've fed off the public energy and enthusiasm… I'm the kind of person that likes to be liked. It suited me… but on the other side of the coin, things move very quickly."
He told of meeting a 14-year-old an an airport, and how she asked for his photo. He was speaking to former Prime Minister Jim Bolger on the phone at the time, and the girl didn't know who that was - which made him realise for some young people, he's been the only Prime Minister they've ever known.
Mr Key also defended some of the tougher decisions he had to make.
"When you're Prime Minister you often have to make decisions and comment on things without perfect information. You can’t be prepared for every question in every situation and you just simply have to trust your gut," he said.
He also gave an outlook on New Zealand’s future prospects.
"My view of a stronger and better New Zealand is an open globally connected New Zealand where we sell to the world, where we invite capital from overseas, where we’re not afraid of migration, in fact we see great benefits of it."
1:35pm - Mr Key has said "farewell" to his Cabinet colleagues, ahead of formally resigning.
"Bill English will be a fine Prime Minister of New Zealand," he said.
He believes he has made New Zealand a "stronger and better" country in his eight years at the top.
He said while he didn't always agree with how the media portrayed him and his policies, it was a "thoroughly professional working relationship".
"I'm gonna miss your party this year, so sorry about that."
Mr Key plans to stay "below the radar" after the Christmas break.
He also encouraged "centre-right leaders around the world" to continue to advance those core policy issues.
"They haven't always been popular and they might not even be that trendy at the moment as philosophical policies, but we succeed as a nation when we're globally engaged," he said.
1:30pm - John Key is about to speak to the media for the last time as Prime Minister.
1:25pm - Patient Bill English is "totally ready to be Prime Minister", writes Newshub political editor Patrick Gower.
"The simple fact is that English has been there, done that. He knows his stuff. He's got a big heart and a big brain. He found that little bit extra today in an accomplished news conference.
"English clearly showed he wants to be his own Prime Minister. He will not be John Key II - more like Bill English 2.0."
12:10 - Labour leader Andrew Little has congratulated Mr English in a statement, but says his challenge now is to prove there will be a difference.
"Is the change in leadership really going to make this Government understand that thousands of New Zealander don't have a roof over their heads, or can't get the hospital care they need, and that parents worry that their kids are not getting the education they deserve," he said.
"On many issues, English's values aren't New Zealanders' values. He voted against marriage equality. We know he favours privatising prisons and selling state houses. New Zealand has moved on. But Bill English hasn't. The right wing rump of National under English is now reasserting itself."
11:48 - Discussions around working with Winston Peters are a matter for next year, says the new PM. Mr English says working with the NZ First leader in the past has been "challenging". He didn't rule it out though, acknowledging National may need Mr Peters' support: "Some of the legislation we've been working with has been quite challenging in getting the numbers, so if NZ First are there to assist us, consistent with their rhetoric, then we're happy to have their support."
"We've got a coalition in place, that's naturally who we're working with, and the business of worrying about NZ First I think will arise after an election," says Mr English.
Mr English and Ms Bennett will now begin talks with their coalition partners, including United Future, Act and the Maori Party.
"I've still got to go through the process of ensuring their support for the renewed leadership of the National Party, so I'm not signalling anything about what might be complicated negotiations after an election, but we have partners who are committed to a stable Government. We work together well, they stretch us, we've achieved a lot and it'd be great to have that continue going ahead," says Mr English.
11:47 - "There's an opportunity now to clear the deck somewhat," says Mr English about the backbench.
11:45 - Mr English won't be following John Key's lead and pledging not to raise the pension age, saying that promise was a "product of its time, needed to establish trust".
11:44 - Mr English says the Government can do a better job of supporting New Zealand's most vulnerable people.
Bill English addresses media as the new Prime Minister of NZ (Newshub)
11:42 - The new PM says he won't have time to meet with the Pike River families tomorrow, but he will consider meeting with them at a later date. He says the issue of recovering the bodies of the 29 victims is not one he'll be dealing with in the next 24 hours.
11:40 - Mr English says he's changed his mind on gay marriage and now supports it, after seeing the impact the Marriage Equality Bill has had on couples. He remains against abortion and euthanasia. He would allow a conscience vote on euthanasia though.
11:37 - Mr English says there will be a Cabinet reshuffle "certainly before Christmas" and "there will be change".
11:35 - Paula Bennett, the new Deputy Prime Minister, says: "There is no one that I would rather be standing next to and support than the very soon-to-be Prime Minister Bill English." She says she deeply admires and respects him.
Paula Bennett has been confirmed as Deputy Prime Minister, and says she "deeply admires and respects" Bill English (Newshub)
11:34 - Mr English quotes a poem he heard at a women's leadership conference last week: "Lead, and dig up the diamonds around you".
11:32 - Mr English thanks his wife Mary and their six children, Luke, Thomas, Rory, Bart, Mary and Xavier, saying "their inspiration and support has led us all here".
11:28 - Bill English: "I am pleased to announce that the National Party caucus has just elected me Prime Minister." Paula Bennett has been confirmed as his deputy, and Mr English says he's pleased to have a "smart, accomplished and energetic woman" in the role.
Bill English addressing media after the National caucus voted him in as the new Prime Minister of New Zealand (Newshub)
11:01 - Outgoing Prime Minister John Key is in high spirits as he walks into his final ever caucus meeting. "It's a beautiful day and a great day to be leaving as Prime Minister," he says. His replacement, Bill English, isn't as chirpy, striding through a media scrum: "I'll be speaking later."
11:00 - Michael Woodhouse won't confirm if he wants to be the next Health Minister.
10:58 - Craig Foss on whether he'll be demoted: "We'll have to wait and see."
10:57 - Louise Upston says she's not concerned about a reshuffle, saying she's proud of the work she's done as Minister for Women.
10:56 - Paula Bennett won't stop to talk to media: "I'm gonna get my vote first, see ya later!"
10:54 - Sam Lotu-Iiga says he's not worried about losing his portfolios. He's currently Minister of Local Government, Minister for Ethnic Communities, Minister for Pacific Peoples and Associate Minister of Health. He lost his Corrections portfolio to Judith Collins earlier this year after sustained criticism over his handling of problems at the Serco-run Mt Eden remand prison.
Left-leaning political commentator Chris Trotter doesn't think the Cabinet reshuffle will be as major as some may hope.
"The watchword has been continuity, right from the moment John Key announced his resignation, so sudden and dramatic changes in personnel is not in keeping with the continuity message which has underpinned the transition," Mr Trotter told Paul Henry.
He believes there will be an "elevation" of some existing Cabinet ministers, including Justice Minister Amy Adams.
The leadership race was touted as a time for rejuvenation and change, with a number of backbenchers calling for a more dramatic shift in who was in charge.
But Mr Trotter says the backbenchers' time in the spotlight is now over.
"The sunlight shone briefly upon them, but now the sun, as it want to do, moves on and they are once again in the shade, where they will remain I suspect until the sunlight shines upon them again."
But if former National Party president Michelle Boag is right, a couple of lucky ones might get a look-in and be plucked from obscurity.
"The thing about the backbench is it's very easy for them to imagine they'll be the one and perhaps they should all enjoy the anticipation a bit longer, because the reality is there might be two or three but then everyone else's hopes will be dashed for another year or whatever," she says.
Although Parliament is heading into the Christmas break, Ms Boag believes the speed of a reshuffle would be determined by what events and commitments existing ministers already have.
"I think it's easy to think 'all he has to do is allocate these jobs' but there's huge realignments that have to take place of diaries," she says.
While Mr English and Ms Bennett were the clear frontrunners for the top jobs, both initially faced challengers.
Judith Collins and Jonathan Coleman both put their hands up to replace Mr Key, but pulled out of the running on Thursday when it became apparent Mr English, the current Deputy Prime Minister and Finance Minister, had the numbers to win the vote.
Transport Minister Simon Bridges withdrew his bid to be deputy on Saturday, clearing the way for Ms Bennett to be elected unopposed.