Health Minister David Clark says the restrictions at the border will remain in place for the foreseeable future.
A ban on all foreign nationals coming into the country was announced by the prime minister yesterday, and came into force at midnight.
Dr Clark told Morning Report the ban would not be lifted until evidence showed that the coronavirus pandemic overseas was diminishing.
"[We] aren't expecting advice to lift restrictions in the next wee while."
He said people were going to have to get used to a new norm, including social distancing, self-isolation, washing hands routinely, and other hygienic habits.
"As a community we're going to have expectations of each other, because the only way we're going to get through this is to work together, it's something we're going to have to unite to fight against, because this virus, otherwise, we've seen elsewhere has got the better of countries."
Yesterday, eight more Covid-19 cases were confirmed, taking the total to 28 across the country.
Dr Clark said the numbers had been of concern to people and measures were in place to help prevent a community outbreak.
He said New Zealand was ahead of other countries in terms of the "epidemic curve", but was still on alert.
With the increase in cases overseas and more people heading home, the latest numbers also shouldn't come as a surprise, he said.
- If you have symptoms of the coronavirus, call the NZ Covid-19 Healthline on 0800 358 5453 (+64 9 358 5453 for international SIMs)
And not everyone should be testing for the virus, he said, experts were best-placed to be making the call on who undertook a test.
"We do not want everybody who is worried to come in and be tested. We need to focus the efforts of our public health system and in particular those in the labs... on those who are genuinely at risk and that's something for the clinicians to judge," Dr Clark said.
"We need to focus on prioritising those things which we know are effective, which the public health evidence around the world and the expert evidence tell us works, and that is contact tracing where we have known cases.
"We're at the stage fortunately where we're not where other countries are, where they've had these community outbreaks, we're at the stage where we still can identify where Covid-19 has come in."
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At the moment there are no blanket school closures, and any cases of infected people at schools are being treated on a case-by-case basis, he said.
Logan Park High School was shut for thorough cleaning after one student tested positive for the virus.
More than 100 students who were tested returned negative results, but the Ministry of Health said all of the contacts will remain in isolation for 14 days and monitored for symptoms as a precaution.
Dr Clark said all options were available and if the advice suggested more action was needed at schools then that would be done.
"Officials are working with schools at how to best mitigate any risks, one thing that schools have in their favour is that for schoolchildren, we know who's there, we have rollcalls and we can trace any cases ... there are patterns of behaviour at schools that make contact tracing easier than in many other circumstances."