Prime Minister Jacinda Ardern says legislation will be drafted for making the voting age 16 after the finding of the Supreme Court, but whether it passes is a matter for the whole Parliament.
The Supreme Court this morning declared the voting age of 18 inconsistent with the Bill of Rights Act. Any change would require the backing of three quarters of MPs, or a majority vote in a referendum.
Ardern said given the requirement, it "should not just be a matter for consideration by the government of the day alone, but for the Parliament as a whole".
Cabinet had discussed the matter today and decided to draft a piece of legislation with a proposal to lower the age to 16 for the whole of Parliament to consider, she said.
If supported, it would not take effect for the next general election, with the Electoral Commission crucial to the process, Ardern said.
"I cannot tell you currently how any member of this House will vote on this proposed law including Labour, as we've not met or discussed it as a caucus."
She hoped parties would be able to have an open discussion and vote on the proposal on its own merits.
"I personally support a decrease in the voting age but it is not a matter simply for me or even the government.
"For me it's alignment around some of the responsibilities and rights that are already apportioned at these different ages - but, look, I accept different politicians will have different views. Mine is one of 120."
Asked if she would trust her decisions from when she was 16, she said the line had to be drawn somewhere.
"I joined the Labour Party when I was 17, so why not?
"The different ages for when you're able to legally engage in different activities is spread out across a range of different age groups - predominantly 16, 17, and 18 - and so there isn't one cut-off point where you can say in law this is where New Zealand treats you as an adult."
Whether an issue was a conscience vote or not would be for the Speaker of the House to determine, Ardern said.
"I can't say at this stage the nature of the vote or indeed how Labour members will choose to vote. What I can say is that on this kind of matter I think we should remove the politics, we should put it to Parliament, and we should let every MP have their say."
Green MP Golriz Ghahraman said MPs had a responsibility to act before next year's election.
"This isn't a Green issue. This isn't even an issue of young people calling to the government for their rights," Ghahraman said.
"This is the New Zealand Supreme Court saying we are in breach of the Bill of Rights Act."
Ghahraman said many of the arguments against young people voting were also used against women's suffrage.
"Are we smart enough? Are we educated enough? Are we good enough to vote? It should never be about those arbitrary standards."
National leader Christopher Luxon said his party did not see a need for change.
"Ultimately, you've got to draw a line somewhere. We're comfortable with the line being 18," he said.
"Lots of different countries have different places where the line's drawn and, from our point of view, 18 is just fine."
National's Justice spokesperson Paul Goldsmith said the party as a whole did not support any lowering of the age, and would keep the voting age at 18.
ACT leader David Seymour also vowed to fight any attempts to lower the voting age.
"We don't want 120,000 more voters who pay no tax voting for lots more spending. The Supreme Court needs to stick to its knitting and quit the judicial activism."
Ardern said the Supreme Court's findings did not mean the law was required to be passed. Instead, the Attorney-General - the MP who is considered the top lawyer for the Crown, in this case David Parker - must notify Parliament within six days.
The notice is then referred to a select committee, and ministers must present a government response within six months.
"Because of the Supreme Court's decision, this has to go to select committee anyway ... you might as well put alongside it the ability for Parliament to make a decision. It takes no extra time, really, as a result."
Questioned over the possibility of the referendum, Ardern said an in-favour result would still require Parliament to change the law, "so you'd still be back before Parliament, still requiring a super majority, so it's an additional step without necessarily a different outcome".
Result long-time coming - activists
Today a small cohort of the group were inside the courtroom, teary eyed and nervously awaiting the final words of Justice Ellen France as she read the decision.
The Supreme Court agreed the current voting laws are breaching the Bill of Rights Act.
Make it 16 leader Anika Green said the result had been a long time coming.
The group have argued that important life decisions and responsibilities start at that age - like driving, paying tax, leaving school - and voting should be one of them.
Their case has focused on the Bill of Rights Act, and claim current laws are breaching the protections to be free from discrimination on the basis of age.
The Supreme Court made a declaration of inconsistency, which is a formal statement by a court to say a law is inconsistent with fundamental human rights which are protected under the Bill of Rights Act.
The judgement also criticised the Attorney-General's argument that a declaration would be premature, and Parliament has postponed the question of lowering the age until there is more democratic support.
A Royal Commission Report in 1986 said that a "strong case" could be made for reducing the voting age to 16, and told Parliament to keep it under review.
Make it 16 Campaign co-director Caeden Tipler said a voting age of 18 could not be justified as 16- and 17-year-olds were also subject to adult decisions.
Tipler said if parliament did not decrease the age, they would be "upholding a human rights violation".
One of the team of lawyers who worked on the Make It 16 campaign, Graeme Edgeler, said if passed, about 200,000 people could be eligible to vote in the elections,.
However, he did not think it would happen before the next general election.
"Because you know if this goes through an ordinary process even if they were to introduce it in a week or two, you know, it could take six months with the select committee, and then we are getting awfully close the elections, where enrolments has already started happening and the electoral commission has already sort of got its systems in place."
He told Checkpoint if passed, a lowered voting age could be possible by the next local body elections, in three years time.
Minister of Justice Kiri Allen told Checkpoint she personally supported the proposal and said that the issue of lowering the age would be advanced as one, and applicable to both the local government and general elections.
Changes also underway for local government
The Independent Electoral Review Panel published a consultation document seeking feedback on a myriad of electoral changes in September and will consider things like lowering the age.
A second round of consultation will take place next year for that.
Future for Local Government Review also proposes a raft of changes to boost participation in local elections, one of the most direct is to lower the voting age for local councils to 16.
Earlier this year - before the local body elections - more than 70 signatures of mayors, deputy mayors and councillors was presented to parliament in support of lowering the voting age.
Decolonising the electoral system
Make it 16 Māori activist Quack Pirihi said the Supreme Court's denunciation of the voting age could also help towards decolonising the electoral system.
Pirihi said the move presented an opportunity to include rangatahi Māori who had previously been excluded.