NZ First is out of Parliament, in a blow that will fuel speculation about whether Winston Peters has fought his last election campaign.
Act's David Seymour and Greens' James Shaw and Marama Davidson surged ahead to grab 10 MPs each.
Another victory story comes after a nailbiting race in Waiariki, where Rawiri Waititi edged out Labour's Tāmati Coffey to bring the Māori Party back.
The night was an absolute bloodbath for Collins' National Party. It came in well under 30 per cent — a result that would give it about 35 seats. That is 20 fewer than the last election.
Walking out her front gate in Sandringham last night, bound for Labour HQ, the Prime Minister was greeted by raucous cheers as the crowd gathered close in to greet her.
Ardern arrived at the Auckland Town Hall to scenes of jubilation and was joined on the stage by her partner Clarke Gayford and fellow Labour MPs.
"Tonight New Zealand has shown the Labour Party its greatest support in at least 50 years," she told supporters.
She acknowledged voters who had switched allegiances from National.
"For those amongst you who may not have supported Labour before... to you I say thank you. We will not take your support for granted."
She said Labour would be a party which works for "every New Zealander".
Labour was committed to key infrastructure, 100 per cent renewal electricity, the environment and supporting those at risk.