National and ACT have become "vanishingly irrelevant" in Parliament following the Greens' acceptance of the cooperation agreement offered by Labour, a politics professor believes.
The deal has locked in a political arrangement that will see Labour and the Greens "monster the Parliament" for the next three years, according to Massey University's Richard Shaw, with a combined 74 of 120 seats held by the parties.
Labour's landslide victory earlier this month saw the party secure its second term - and the power to govern alone without the need for a coalition. However, Prime Minister Jacinda Ardern revealed on Saturday that she has offered the Greens two ministerial positions in a post-election deal despite Labour winning the majority - which the Greens accepted in a lengthy conference call last night.
According to the agreement, the Greens will support the Government on procedural motions in the House and at select committees, and cannot oppose the Government on confidence and supply matters - providing Labour with extra stability. The parties will also commit to three areas of cooperation regarding climate, environment and child and community wellbeing issues.
"The National Party, ACT, and the Māori Party - assuming that the specials mean they keep Waiariki - are vanishingly irrelevant to what occurs in the Parliament," Shaw told Newshub on Saturday.
He says the agreement - which the Greens will sign in a ceremony on Sunday - marks the largest political alliance in New Zealand's parliamentary history.
"It's really hard to overstate how much the legislative agenda and the executive agenda will be driven by Labour with some support from the Greens, it's a really remarkable state of affairs," Shaw says.
"And if you're a National or ACT MP, you would be sitting there thinking, 'Shit, what am I going to do for the next three years? I'm going to be surrounded by Opposition members in all of the select committees' - it's just dominated by Labour's policy."
The Greens nabbed an additional two seats in the election, including Chlöe Swarbrick's unprecedented win in the Auckland Central electorate. Yet the number of portfolios held by the party has dropped by more than half, with co-leaders James Shaw and Marama Davidson the only two to be given ministerial portfolios outside of Cabinet. MPs Eugenie Sage and Julie Anne Genter - who have served as the Minister of Conservation and Land Information and Minister for Women respectively - were not offered roles under the agreement.
Under the previous Labour-New Zealand First coalition, the Greens had held four executive positions with 10 portfolios between them - their presence now "significantly diminished" in the executive branch of Government.
"It's more interesting than I thought it would be - the Greens might be, after the euphoria of election night, a wee bit disappointed with the number of portfolios they have in this Government," Shaw says.
James Shaw, who will maintain his position as the Climate Change Minister, has also been offered the role as Associate Minister for the Environment with a focus on biodiversity. Davidson, who has never held a ministerial position before, was offered the new position of Minister for the Prevention of Family and Sexual Violence as well as Associate Minister of Housing, with a focus on homelessness - two "stonking great, big-ticket public policy issues", says Prof Shaw.
He also noted that provisions have been made under the agreement for the Greens to remain part of the broader policy-making process. In their roles, James Shaw and Davidson will be members of ad-hoc ministerial groups where informal decision-making is completed before the policy is presented to Cabinet, Prof Shaw says.
In the other outlined areas of joint interest - such as the environment, child wellbeing, and homelessness - Greens' spokespeople will be able to have discussions with the relevant Government ministers, allowing them some input in developing policy.
"So outside of the four portfolios held by Shaw and Davidson, there will be these other areas where there will be, I imagine, [a] quite intensive engagement between the Greens and the relevant Labour ministers," Prof Shaw explains.
Although the deal will allow the Greens' involvement in shaping and developing policy in the areas relevant to its values, beyond that, the party can continue carving their own path.
"Beyond the four areas they are responsible for, beyond that they can differentiate themselves. The Greens don't have to agree with anything the Government chooses to do outside of the areas it is signed up to."
Speaking to reporters on Saturday, Ardern said the arrangement allows Labour to have "both the benefit of continuing with a strong mandate and delivering on those things that we campaigned on, whilst using the skills and expertise from the Greens".
"On election night, I said I wanted to govern for all New Zealanders and to reach as wide a consensus on key issues as possible," she said. "This agreement does that while honouring the mandate provided to Labour to form a majority Government in our own right."
Newshub will be livestreaming the ceremony as the Greens sign the agreement at 11am on Sunday.