There are 40 new cases of coronavirus confirmed in New Zealand today.
Director-General of Health Ashley Bloomfield told reporters there were also three new probable cases.
There were now 155 cases of confirmed and probable cases, and he said the daily tally would now include probable cases.
The probable cases had returned a negative result, but their history and symptoms showed they had Covid-19, and they were treated the same as if they had returned a positive result.
Details of the cases would be updated on the Ministry of Health website.
Six people who had attended the Hereford Conference in Queenstown had now tested positive, Bloomfield said.
Separatley, six cases were in hospital, and they were all stable, and none of them required ICU treatment.
Bloomfield said there was a community transmission case in Orewa, who had been on a tour to Milford and presumably came into contact with an overseas traveller.
Both he and his partner had tested positive, Bloomfield said.
Asked if losing the sense of smell was a symptom of Covid-19, Bloomfield said it was an incidental finding and researchers were following that up now.
Watch PM's full media briefing here
12 PEOPLE FULLY RECOVERED FROM VIRUS: PM
Prime Minister Jacinda Ardern said it is positive news that 12 people with coronavirus have fully recovered.
"I obviously expect that number to continue to increase."
Six people are in hospital with Covid-19, but none require ICU care.
The underlying principal for alert level 4 is to reduce contact to people to the "bare minimum" so the simplest thing Kiwis can do is stay home, she said.
"That's how we will save lives."
Ardern said we needed to pay gratitude to those working in essential businesses, "the necessities of life", and we can show that by staying home now.
"You are literally putting those at risk who have to be there, like our hospital workers."
"You will be able to leave your house for a walk, but don't congregate. If you live alone, you can have contact with someone outside of your home but limit to that. When you do "essential errands", keep your distance from those working. This is life that won't be normal."
The Covid committee is working to provide more updates on what are essential services and the starting point is closing as many businesses as possible. If they find others need to be open, they will do that.
"We will be ready to be responsive... We have never shut down our country before."
If you are not providing a necessity of life, you should close, the PM said.
Ardern said there had been a range of decisions made for people on temporary and student visas.
"This event is unprecedented in New Zealand - we have never shut down our country in 48 hours before."
For anyone who is stuck around the country, they will be able to get home and arrangements can be made.
Ardern said she simply wasn't willing to wait for answers to logistical questions before shutting the country down.
• Watch full Ministry of Health briefing here:
Health workers might need to self-isolate from their own family if they were caring for someone who had Covid-19, Dr Ashley Bloomfield said.
"I'm sure everyone would be looking to minimise the risk to their household members, including health workers."
"Anyone who has been tested is expected to be in strict self-isolation until they are advised of the result."
All new cases that he had information on, about a third of the 40 new cases, had a link to overseas travel or to close contacts of an already confirmed case.
Most cases in New Zealand were still related to overseas travel, he said.
"At this point we are classifying four cases as 'community transmission' - three in Auckland and one in the Wairarapa."
Contact tracing was under way for all of those cases.
He said he was not aware of any confirmed cases among health workers, and there was one confirmed case in an Auckland rest home.
People in the rest home, including staff who may have been exposed, were being looked after in a "bubble".
Aged care residential facilities were told to put in place strict protocols for visiting weeks ago.
More than 900 tests were carried out yesterday, bringing the total to over 8300 tests.
Bloomfield said there was a clear consensus among public health professionals and scientists that moving to alert level 4 sooner rather than later gave New Zealand the best chance to break community transmission.
An increase in testing capacity meant that testing could now take place in a school, for example.
There would be strict rules on visiting people in hospital during the lockdown period, he said.
He said millions more masks were being produced, so he was confident about the personal protection equipment (PPE) stocks in New Zealand.
