Explained: What happens next after Prime Minister Jacinda Ardern announces resignation

Prime Minister Jacinda Ardern dropped a political bombshell on Thursday revealing she is stepping down as leader of the country. 

Ardern's out-of-blue resignation came just nine months out from the 2023 General Election. 

"Being Prime Minister has been the greatest honour of my life and I want to thank New Zealanders for the enormous privilege of leading the country for the last five and a half years," Jacinda Ardern said. 

"Withholding such a privileged role comes responsibility, including the responsibility to know when you're the right person to lead, and also when you're not.  

"I have given my absolute all to being Prime Minister but it has also taken a lot out of me. You cannot and should not do the job unless you have a full tank, plus a bit in reserve for those unplanned and unexpected challenges that inevitably come along. 

"Having reflected over summer I know I no longer have that bit extra in the tank to do the job justice. It's that simple."

Despite Ardern's departure as Prime Minister, she will stay on as the Mt Albert MP until April to spare the country a by-election.

What happens next? 

Newshub political editor Jenna Lynch said the Prime Minister's resignation came as a "total shock". 

"This came out of the blue. She had been saying in every interview that she would definitely be running for another term but over the summer she said that she has reflected and has not got enough left in the tank for this election."

The race for the next Prime Minister now begins with Ardern revealing she will be leaving her position before February 7. 

Lynch said the Labour caucus will vote for a new leader on January 22. If a candidate gets more than two-thirds of the caucus support and is elected, Ardern will issue her resignation to the Governor-General. If no one can get this level of support, the contest will go to the wider membership.

"The Labour Party is going to be holding a vote on Sunday in three days to elect a new leader and therefore the next Prime Minister," Lynch said. 

But despite the quick timeframe for the vote, it's still unclear who the new leader might be. The obvious contender, Finance Minister and Deputy Prime Minister Grant Robertson has already ruled himself out. 

"I am not putting myself forward to be a candidate for a leader of the Labour Party," Robertson said on Thursday afternoon. "In 2014 when I failed to secure the leadership of the Party for the second time, I said I would not put myself forward again and my position has not changed," he said. 

Other frontrunners for the position include Minister of Education, Police, and the Public Service Chris Hipkins, who was front and centre during the COVID-19 pandemic. Another option is Minister of Immigration, Transport, and Workplace Relations & Safety Michael Wood who is regarded as a competent Minister. 

Minister of Justice Kiri Allan is also a possibility. 

What does it mean for the election? 

Lynch said Ardern's resignation means "the election just got turned on its head". 

"The Prime Minister just announced the election date as a parting gift to the political scene, October 14, and now the race is truly on because National will be rubbing its hands together. 

"It doesn't know what it's up against but Jacinda Ardern has always been the weapon of the Labour Party. Her brand is so intrinsically linked with Labour's success and having her gone… you would think the strategists over at National would be feeling pretty good right now," she added.