“We have done this together,” Ardern said.
“There is no widespread community transmission in New Zealand. We have won that battle.”
But she warned that while coronavirus was “currently” eliminated, the next challenge for the government was the risk of the numbers creeping up again.
“Elimination means we may well reach zero but we may well then have small numbers of cases coming up again”, she said.
“That doesn’t mean we have failed, it just means that we’re in the position to have that zero tolerance approach, to have a very aggressive management of those cases and keep those numbers low and fading out again.”
Ardern said about 400,000 people would return to their workplaces on Tuesday as the country’s lockdown was dialled down to level three from level four.
The shift has only a small effect on the social lives of New Zealanders, who are still being asked to stay home and practise social distancing.
On Monday, health officials reported the country’s 19th death from 1122 confirmed coronavirus cases.
The latest death was a woman aged in her 90s, linked to the St Margaret’s residential aged care facility in Auckland.
All of New Zealand’s deaths have been elderly people, with the majority from clusters linked to either the St Margaret’s home or Rosewood rest care home in Christchurch.
Hospitalisation rates have shown the strength of New Zealand’s public health response; fewer than 90 people have been to hospital with the disease.
Ardern thanked citizens for persisting with a month-long lockdown that included “the strictest constraints placed on New Zealanders in modern history”.
“There is no widespread underlying community transmission in New Zealand. We have won that battle,” she said.
“It’s worked and we’ve done it together.”
Many industries, including the mammoth tourism and aviation sectors, will remain a shadow of their former selves during level three.
Others, such as construction and forestry, will return to work, while creches and schools will admit the children of those who must work away from home – up to year 10.
The return of takeaway food will be the biggest morale-booster of the lockdown.
Restaurants can open from Tuesday for delivery, drive-through or contactless takeaway.
New Zealanders have been chatting on social media about the return of their favourite foods, with former prime minister Helen Clark joyfully nominating Thai food on Twitter as her first takeaway meal under level three.
Ardern, her protege, said “the thing that I’m actually looking forward to is really just the chance to support some small businesses”.
“On my local walks … I see first-hand those cafes and places that have been closed down for a number of weeks,” she said.
“I’m looking forward to a chance to – like everyone – show them a bit of love.”
AAP with Stuff, staff reporters.