Jacinda Ardern says she expects to be Prime Minister soon and wants to get down to negotiations this weekend.
Ardern fronted media in Auckland after special votes saw Labour and the Green Party gain a seat each, with National dropping from 58 on election night to 56.
"These results show that the majority of New Zealanders voted against the status quo," Ardern said.
"[They] voted for change. I would be proud to be a Prime Minister in a changed Government.
"We will continue our negotiations in earnest with potential support parties, beginning this weekend."
Peters has said NZ First wants to have a decision made on who to support by this Thursday. Asked directly if she expected to be Prime Minister after those talks, Ardern said yes.
"That is what we are in these negotiations for. That's what we campaigned for. To be in a position to make change.
"I ran a strong campaign on behalf of Labour to be in the position to be Prime Minister, to lead New Zealand, and to improve the lot of all New Zealanders. That is what these negotiations are now about."
Ardern was joined by her negotiating team including deputy leader Kelvin Davis and finance spokesman Grant Robertson. The mood was upbeat, despite some regret that Labour couldn't quite capture a second seat.
On election night Ardern told supporters she hadn't done as well as she would have liked, would take responsibility for that, and had called Bill English to acknowledge the performance of his party.
Two weeks later, Ardern was bullish on whether National had any kind of mandate or advantage as the largest party, saying most New Zealanders had voted for change and under MMP it was up to the major parties to negotiate.
She acknowledged there was now a need to get down to negotiating if the Thursday deadline was to be met.
"We are focussed on making sure we can find resolution as quickly as possible. But we will do that responsibly. We will make sure that we take the time needed and try and strike the balance between moving quickly but moving responsibly."
Ardern said she wanted to continue negotiations this weekend, but wouldn't confirm that would be with NZ First.
"My expectation is we will have a conversation this weekend around our next meeting.
"I haven't set clear timelines with New Zealand First yet. But I expect all parties will be moving as quickly as we are able to."
Asked if she thought the Thursday deadline could be missed, Ardern said that wasn't her current expectation.
"But what I will say is we will do this responsibly."
Peters has said his party was yet to decide on its preferred governing framework.
Possible options open to the party include a full coalition inside Cabinet, a support agreement offering confidence and supply in return for some ministerial posts outside Cabinet, to sitting on the cross benches offering support on case by case basis in return for minimal policy gains.
Ardern said she would be proud to lead a Government that was reliant on NZ First. Asked if she would be comfortable leading one where NZ First sat on the cross benches, she said her focus is on forming a "stable, durable coalition government".
"Beyond that, I'm certainly not going to reveal anything that happens behind closed doors."