Source: Getty Images AsiaPac
"Moving to level one (restrictions) is the dividend of everyone's hard work," Ms Ardern said.
"This is really good news for the person concerned, and it's also something the rest of New Zealand can take heart from," NZ's director general of health Ashley Bloomfield said.
Almost 300,000 tests have been carried out in New Zealand, where 1504 have contracted the virus and 22 have died.
New Zealand recorded its first case of COVID-19 on 28 February 28, prompting the government into firm and fast action against the deadly virus.
On 23 March, when cases numbered 100 for the first time, Ms Ardern imposed a strict lockdown which would last 51 days.
That lockdown kept Kiwis inside their houses, except for trips for health reasons or the supermarket.
Australia did not enact such tough restrictions and still has over 400 active cases.
New Zealand will maintain strict border controls and contact tracing to ensure it can contain any future waves.
"We are not immune to what is happening in the rest of the world," Ms Ardern said.
"But unlike the rest of the world, not only have we protected New Zealanders' health, we now have a head start on our economic recovery.
"That's because at level one, we become if not the most open then one of the most open economies in the world."
Upon learning of the last case recovery, Ms Ardern said she danced around her lounge room.
"I did a little dance ... I showed Neve and she was caught a little by surprise but she joined in having absolutely no idea why I was dancing around," she said.
The New Zealand government has also ended its state of national emergency, though many emergency powers remain with authorities after legislation passed last month.
Michael Baker, Professor of Public Health at the University of Otago, said the move to level one restrictions was "only the first battle in what will be a long-term war against this virus".
"This risk will rise again in New Zealand as we gradually increase the numbers of incoming travellers. It will also rise during the coming winter when coronaviruses are more transmissible," he warned.
Debate will now shift to the re-establishment of regular travel across borders, with Ms Ardern pledging to open Australian travel first, but only when it is safe to do so.
People in Australia must stay at least 1.5 metres away from others. Check your state’s restrictions on gathering limits.
Testing for coronavirus is now widely available across Australia. If you are experiencing cold or flu symptoms, arrange a test by calling your doctor or contact the Coronavirus Health Information Hotline on 1800 020 080.
The federal government's coronavirus tracing app COVIDSafe is available for download from your phone's app store.
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