New Zealand has 102 confirmed cases of coronavirus and is now at alert level 3 - and will move to level four for likely at least four weeks from Wednesday.
Alert level 3 means the risk of the potentially deadly virus not being contained and there will either be community transmission of the virus or multiple clusters breaking out.
Level 4 means people are instructed to stay at home, schools and universities closed, as well as non-essential businesses, major reprioritisation of health services, and severely limited travel.
Essential services will be open at all alert levels, but level 3 means limited travel in areas with clusters of Covid-19 cases, affected educational facilities closed, mass gatherings cancelled, public venues closed (such as libraries, museums, cinemas, food courts, gyms, pools, amusement parks), some non-essential businesses closed, and non face-to-face primary care consultations, with non-elective services and procedures in hospitals deferred.
Prime Minister Jacinda Ardern has just told the nation "we are all now preparing as a nation to go into self-isolation in the same way we have seen other countries do. Staying at home is essential".
That would give the health system a chance to cope, she said.
Workplaces now had to change, while essential services had to ensure a 2m physical distance between people. Schools would close from tomorrow, except for those people who work in essential services with kids at schools.
In a tweet, he said: "The evidence is mounting that the best thing NZ could do is make the hard decision to go to extreme shutdown now.
"The number of new cases coming from offshore means community transmission will get established without absolute precaution."
The Prime Minister today said that, when the country moves to alert level four, contact tracing would continue and testing would go on "at pace" to find out where cases are.
"If we flush out cases we already have, and slow down transmission, areas could move out of level 4," she said.
Community transmission had a lag time, and these measures would be in place for at least four weeks, she said.