The Labour and Greens leaders have signed off on the cooperation agreement between the parties today.
Prime Minister Jacinda Ardern and deputy Kelvin Davis met with Greens leaders Marama Davidson and James Shaw at parliament for the signing.
Arden said it was "fantastic to be able to formalise the cooperation agreement" between the parties.
"For us, 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.
"It also importantly for the government brings stability. In this agreement, there is agreement from the Green Party not to oppose the government on important votes like confidence and supply, to support us in procedural motions and iatselect committee."
The Prime Minister said this arrangement gave the government that "extra surety" that they could govern with the mandate NZ had given them. She added that it also allowed the government to draw on the skills across parliament.
She said the agreement was unique in that "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. For us, this represents the evolution of MMP."
The Greens leaders expressed delight at the agreement and said they were deeply honoured to be named as ministers in the upcoming government.
"The Greens had campaigned on working productively with Labour to get things done, especially in the area of climate change and inequality. So we are really proud of signing this agreement today," said Davidson.
"We know that we want to continue working in those areas of climate change, inequality, biodiversity, we are running out of time.
"What we have achieved here has also allowed us to keep pushing on those important areas of work which the Green Party has always maintained. As well as, keeping and protecting our independent Green Party voice."
Davidson said that they had received a "super majority" of support from Green Party members for the cooperation agreement at their meeting yesterday with the party. She said a 75 percent vote of support was required and they had received "well over 85 per cent."
Yesterday, Ardern said she had offered Davidson the roles of Minister for the Prevention of Familiy and Sexual Violence and Associate Minister with a focus on homelessness, while Shaw would continue as Climate Change Minister and Associate Environment Minister.