New Zealand Prime Minister Jacinda Ardern says she hopes a cooperation agreement with the Greens brings an extra level of stability to her second term in government.
Ms Ardern's Labour party scored a thumping win in the October 17 poll, securing a parliamentary majority in its own right.
However, the 40-year-old has spent the last fortnight negotiating with the Greens, and on Sunday signed a deal that gives the left-wingers two ministries.
"This agreement is unlike any other. It does not require consensus to be formed. It allows the parties to take their own positions on issues where that is important, but offers to work together in other areas too," Ms Ardern said.
"This cooperation agreement represents the relationship that the Labour Party and the Green Party have formed over the last three years and the continuation of that.
"Importantly for the government (the deal) brings stability."
Greens co-leaders James Shaw and Marama Davidson will hold the climate change and family violence portfolios respectively, and both will sit outside of cabinet.
The Greens secured an increase to their vote in last month's election by pledging to support Ms Ardern's hyper-popular government.
"The Greens campaigned on working productively with Labour to get things done, especially in the area of climate change and inequality," Ms Davidson said.
"We are really proud of signing this agreement today."
The decision to accept the Labour offer came down to a vote of grassroots Greens members, of whom 85 per cent voted in favour.
Ms Davidson and Labour deputy leader Kelvin Davis, who are both Maori, spoke in te reo Maori at the official signing.
The parties have also agreed to progress a shared policy agenda on climate change, environment, child wellbeing and "marginalised communities" issues.
In her second term, Ms Ardern will also be without a major "handbrake" encountered in her first term in office; Winston Peters' New Zealand First party.
The populist party did not see re-election, meaning the two parties can progress issues they agreed on over the last three years, but were stymied by Mr Peters.
"It's a new parliament and a new day," Mr Shaw, a long-time adversary of Mr Peters, said.
One of those issues, implementing pill testing at festivals, could happen soon.
"That is a basic safety issue. That is about saving lives and I do think people appreciate that," Ms Ardern said.