"For now, I ask that New Zealanders do their part".
New Zealand on Wednesday reported 47 new confirmed cases of coronavirus and three probable cases, bringing the total to 205.
People are ordered to stay inside and non-essential services are being shut down, coming as the number of cases rises to 205 today. These returnees will be screened for symptoms, and quarantined if they could possibly have coronavirus.
People just getting fresh air should be able to without being told to go home by police, and some common sense was needed in their approach. If not, they would also be quarantined.
'Each of you has a role in helping to save a life, ' she said.More news: Trump says 'a little upset with China' over coronavirus
Ms Ardern said the pandemic required "a significant and coordinated response by and across central and local government" and for each citizen to minimise their contact by self-isolating.
'Breaking the rules could kill someone close to you, ' Ardern said in a press conference on Wednesday.
She did not mention the use of campervans for quarantine, but the Ministry of Health has confirmed that a camp of 50 self-contained motorhomes in Christchurch has been prepared for returning Kiwis, and similar set-ups are being organised in Wellington and Auckland.
Up to 10,000 Kiwis could come home by the end of the month, and some of them may pose a health risk.
People in lockdown should stick to their "bubbles" which, for most people, are those in their households.
People without a valid reason to be outside can be reminded of their obligations, she said.More news: Taoiseach Leo Varadkar announces new Covid-19 measures and protections
Parliament received the Covid-19 epidemic notice today, meaning New Zealand is officially now in a state of emergency. "Don't think about congregating with anyone else, don't think about a lunch or a catch-up, or visiting a friend in their home", she said.
Prime Minister Jacinda Ardern has emphasised a powerful message to New Zealanders ahead of the coronavirus lockdown: you are not alone.
"Its a state of emergency to preserve our way of life", Ardern said in a speech in parliament on Wednesday, declaring a state of national emergency.
"You may not be at work but that doesn't mean you don't have a job".
'[It will] ensure the government has all the powers it needs to slow the spread of Covid-19 and reduce its impact, ' she said.
Civil Defence director Sarah Stuart-Black on Wednesday said she expected the powers to be used where necessary. "Then we'll begin to know how successful we have been". We will have a lag and cases will increase for the next week or so.More news: NFL GMs call for draft postponement as team facilities close