Foreign Minister Winston Peters has announced a "do not travel" guideline - the first time it has been done in New Zealand.
"We are raising our travel advice to the highest level: do not travel," Mr Peters said.
"This is the first time the New Zealand Government has advised New Zealanders against travelling anywhere overseas. That reflects the seriousness of the situation we are facing with Covid-19.
"New Zealanders who travel overseas risk contracting Covid-19. At the same time, health care systems in many countries are under strain and do not have the capacity to support foreigners."
Australia announced similar "do not travel" advice yesterday, and Prime Minister Jacinda Ardern welcomed it as a measure to protect people from the disease.
Peters also yesterday told all New Zealanders abroad to come back.
"If you're travelling it's very likely you could be shut off very shortly," Peters said yesterday.
"If you can get home, come home now."
He reiterated that again today.
"Borders are closing. You may not be able to return to New Zealand when you had planned to. You should therefore organise to come home now.
"If you choose to remain overseas despite our advice, the ability of the New Zealand Government to provide consular assistance may be limited due to internal travel restrictions and the suspension of services."
He said Kiwi expats would need to consider their personal circumstances and do what is best for them and their family.
"Those New Zealanders who decide to remain overseas will need to ensure they are well prepared. New Zealanders in this situation should keep themselves safe by following the advice of the World Health Organisation (WHO) and local health authorities. New Zealanders overseas are also encouraged to register on SafeTravel so they can receive important updates on Covid-19.
"In times of crisis, we will see the best in people, and the worst. To those who say we should not welcome our fellow citizens back to our shores I ask that you put yourselves in their shoes.
"All New Zealanders need to show their compassion for one another. Now, more than ever."