Jacinda Ardern says she's taken on the worst job in New Zealand politics, but she's committed to bringing "relentless positivity" to the party and next month's election campaign.
An hour after being named opposition leader following Andrew Little's resignation, the 37-year-old's message to NZ Prime Minister Bill English was not to be complacent.
Ardern's giving herself 72 hours to take stock of Tuesday's seismic events before bowling head on into "vibrant" campaigning alongside her new deputy, influential Maori caucus MP Kelvin Davis.
They'll commit to core elements of the Labour campaign so far, but Ardern has vowed to put their own stamp on it as well.
Within the party there's a renewed sense of optimism, including from Trevor Mallard who suggested Ardern could take 10 points from National on current poll figures.
"I think she's fiercely intelligent, very much like Helen Clark in that way, but I think she's got the advantage of youth and vibe and an ability to connect, probably better than Helen did before Helen was PM," he said.
Both Ardern and Davis were elected unanimously, following nominations by Little and Grant Robertson respectively.
Despite his resignation from the leadership, Ardern says Little will remain a senior caucus member and minister in any government she leads.
Ardern told reporters she had been genuine in her repeated statements in the past that she wasn't interested in the job, but things are different now.
"These are extraordinary circumstances," she said.
"Everyone knows that I have just accepted - with short notice - the worst job in politics. But I also welcome this job."
As to whether she's capable of leading a coalition of Labour, the Green Party and New Zealand First, Ardern said she was the president of an international youth organisation with members from Lebanon, Palestine and Israel.
"I think I can do this," she said.
All eyes will now be on the next round of polls.
Two media polls this week put support for Labour at 24 per cent, while Labour's own pollsters, UMR, recorded 23 per cent.
Little said as leader, he took responsibility for those numbers.
