The left-wing party charted 16 per cent, up four points, in a new TVNZ poll released on Monday, their best result in the gold-standard survey.
And every point looks set to count as Prime Minister Chris Luxon's ailing coalition seeks to fight off the Labour-led left and avoid being the first one-term government in half a century.
The contest is so close - between both the major parties and the broader right and left blocs - and so tense that one analyst is warning of "unrest" after the November 7 poll.
The latest TVNZ results have Mr Luxon's National and Labour tied on 28 per cent, with a polling average giving Labour a one per cent lead.
Given the collapse of support in major parties, the performance of the smaller players could decide which bloc can cobble together a majority.
A National-led government has never been denied a second term in Kiwi history, but the TVNZ poll makes clear that is a distinct possibility.
"Pretty cool, isn't it," Greens co-leader Chloe Swarbrick told TVNZ after the result.
"New Zealanders have agency. Nothing is set in stone."
On Sunday, both National and Labour held rallies in Auckland to fire up their bases for the poll push ahead.
Based on those events, a month of mud-throwing awaits.
National's campaign slogan of "No New Taxes" is aimed squarely at the Labour challenge, given Mr Hipkins' promise to implement a capital gains tax.
Mr Luxon goes further, adding in the policies of Labour's would-be coalition partners to allege the left will bring in nine new taxes if they win office.
A furious Mr Hipkins called that allegation "bullshit" at his campaign launch, saying Mr Luxon was resorting to "outright lies".
Ben Thomas, a well-respected right-aligned commentator, said National's campaigning was proving effective.
"The attacks are working," he told Radio NZ.
"We've seen a pretty precipitous drop in Labor's polling since March where they peaked in the high 30s.
"Now they're right back neck-and-neck with National, I think about on per cent difference on average between the two."
Labour has run a policy-light small-target strategy so far with a bevvy of attacks on Mr Luxon.
Kiwis haven't warmed to the 56-year-old, a corporate-speaking former executive, and neither have his colleagues, given two leadership challenges this term.
"Christopher Luxon seems to stand for blame, excuses, slogans, no real answers, and New Zealand going backwards," Mr Hipkins told the Labour launch.
"Ask yourself this - after three years of National, are you better off?"
The constant negativity has been cited as a reason the two major parties are polling at their lowest combined levels in NZ history.
Increasingly Kiwis are offering support to the minor parties: not just the Greens, but on the right, NZ First and ACT.
A second possible coalition partner on the left, the Maori Party has collapsed owing to internal issues, but in its place has popped another: Opportunity.
The teal-esque force looks likely to enter parliament and most likely team up with the left, after Mr Luxon ruled them out.
Kiwis are set for a tense six weeks ahead, given the closeness of the race and three years of scrapping and feuding, including over Maori rights.
There is also a desperation in the air given high unemployment and a tough term economically, even with improved forecasts ahead.
The ingredients prompted Mr Thomas to suggest the chance of ugliness after November 7 election from the losing side.
"There's a lot of scope here ... for some unrest after the election," he said.
"We have struggled, in terms of social cohesion, in terms of people buying into democracy, recently.
"You would have these claims of an illegitimate government from at least some quarters."
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