The Greens and Act are both playing coy about their respective gains in the latest polling - and on working with the Opportunity Party.

The 1News-Verian poll out Monday showed Opportunity down two points to 6% - dangerously close to the threshold that would see them out of Parliament without an electorate win.

But both the left and right bloc would need Opportunity's seven seats to form a government.

The Greens made the biggest gains of 4 percentage points, netting them a record 19 seats, and co-leader Chloe Swarbrick gained 2 points to put her third on the preferred prime minister rankings, just six points behind Labour's Chris Hipkins.

She told RNZ the party was not taking anything for granted and would work hard to share its vision with New Zealanders, but the country was in "pretty unprecedented political times".

The Greens would work with "whomever we have values alignment" and that was true of Opportunity - in some areas.

"But I think that there is maybe a little bit of divergence when it comes to the willingness to allow corporations to kind of write the rules when it comes to environmental and climate policy.

"We don't begrudge anyone who's bringing evidence-based policies to the table, but ... there are only two political parties asking for your party vote who are committed to changing the government, and that's the Green Party and the Labour Party."

Swarbrick laughed off questions about the preferred prime minister stakes, saying "you don't join the Green Party because you have grand designs on climbing up the greasy pole".

David Seymour and his Act Party were both up 2 points and - like Swarbrick - not counting chickens.

"We're very grateful for the people saying they will support Act, but we know there's a long way to go and we're going to have to keep working hard to truly earn their vote."

National has ruled out working with Opportunity, and Seymour was initially vague about whether that should change.

"The Act party is here to lock Labour out of government and lock Labour's policies out of the National Party - which has been necessary lately ... we don't mind who we need to work with, notwithstanding there's a few that are non-starters."

Asked if that included Opportunity, he said it was "very hard to know what you're getting with them".

"They seem to have launched with some bold policies that they now say are just ideas; they say they're here to clean up politics and stop big money, but they were founded with a $3 million donation, which is still the largest in New Zealand history. So, look, I can't make head nor tail of them.

"What we hear from Opportunity is 'everyone's a bit silly and they're here to fix it for us', I have another theory: politics might be a little bit harder than the Opportunity Party think, and they're a bit naive."

RNZ has sought comment from the Opportunity Party.

With some advocating for National Party supporters to use their party votes to support the smaller parties in the coalition, Seymour stands to gain.

He and NZ First's Winston Peters criticised National's leader Christopher Luxon for calling it an "insanely stupid idea", saying voters were "often busy, but they're not stupid, and it's never wise to talk down to them".

Te Pāti Māori has made the tactic a core strategy, but Swarbrick aligned closer to National.

"A strategic vote only actually makes sense if everybody, a critical mass of people are on board ... if everybody is running their own strategy, it's not particularly strategic."

She said New Zealanders should be voting for their values and the candidates and policies they believed in.

With Labour leader Chris Hipkins overnight promising to restore the former pay equity legislation within 100 days of forming government, all eyes turn next to the Pre-Election Economic and Fiscal Update (PREFU) when the government opens its books, which he has long set as the trigger for revealing how Labour will pay for its policies.