There have been 11 new cases of coronavirus in New Zealand, the Ministry of Health says.
Director-General of Health Ashley Bloomfield said that brought New Zealand's total to 39 positive cases.
There were five in Auckland, two in the Waikato, one in the Hawke's Bay, two in Wellington and one in Canterbury.
None of the new cases were in hospital and they were all at home self-isolating, Bloomfield said.
The Ministry was investigating whether all were linked to overseas travel.
Countries visited include France, Spain the United States and England.
As of the eight cases confirmed yesterday, a man in his 60s, had been hospitalised in Lakes District Hospital.
Two in Taranaki, a male and female, both aged in their 40s, had recently returned to New Zealand from Egypt.
Foodstuffs South Island chief executive Steve Anderson said supermarkets were under huge pressure right now.
"We don't have a supply issue, we have a demand issue."
He said customers could expect limits on some products. He encouraged customers to shop normally.
"If we all purchase as usual, there will be no problems."
"We may all need to take a deep breath or two collectively."
Bloomfield said the ministry was keeping a close eye on any signs of community transmission in New Zealand.
New Zealand borders closed at midnight last night to non-residents - only citizens and residents are being permitted entry.
The unprecedented move was made in an attempt to prevent widespread community transmission of the coronavirus. It was also influenced by the number of positive cases which had come from overseas travellers, and concerns about whether tourists were self-isolating after arrival.
Earlier today, Prime Minister Jacinda Ardern said New Zealand schools would close where there were positive tests to conduct contact tracing, but they would not be closed generally without a widespread community transmission.
This was the model that had been adopted in Singapore and Taiwan, where transmission of Covid-19 had been slowed.
Shutting schools prematurely could send students to their grandparents to be looked after, and elderly people were more susceptible to coronavirus, Ardern said. It would also take health workers out of the workforce.
The Government was looking for spikes in transmission, Ardern told Mike Hosking on Newstalk ZB.
"If you want to be ahead of outbreaks, everyone needs to be prepared to work from home. Be prepared to cancel non-essential trips. Be prepared to reduce down that social contact. Do that now."