For the first time in New Zealand's history, New Zealand's borders will be closed to everyone in the world except for New Zealand citizens and residents.
The dramatic steps, which come into effect at 11.59pm today comes as an attempt to "protect New Zealand" from the Covid-19 virus, Prime Minister Jacinda Ardern told media tonight.
"Protecting New Zealanders from Covid-19 is our number-one priority."
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But to do that, "we need to slow it down," she said of the disease – Ardern is confident the new rules will do this.
In recent days, Ardern said it has become increasingly clear that the spread of the virus in other parts of the world meant the Government needed to take stronger border measures.
The total number of Covid-19 cases around the world has now surpassed 200,000.
Any retuning New Zealanders will still be required to self-isolate for 14 days upon entry.
The partners, legal guardians or any dependent children travelling with returning Kiwis may also return, but will need to self-isolate as well.
But immediate family members cannot travel by themselves and need to travel with New Zealand citizen or resident family member on the same flight home.
And exemptions are in place for "key workers" in the health sector, Ardern said.
Unlike previous border restrictions, the new rules will apply to would-be travellers from the Pacific Islands.
Ardern tonight again reiterated her warning to anyone who does not follow the self-isolation rules, that they would face consequences.
On Saturday, Ardern announced that every person from every country, excluding the Pacific Islands, would have to self-isolate for 14 days when coming to New Zealand.
But she made clear tonight that further steps needed to be taken.
"The rapidly worsening global health situation means that the threat to people's health in New Zealand has risen."
The decision was made despite the fact there is still no evidence of a community outbreak in New Zealand.
There are now 28 cases of Covid-19 in the country – all have overseas links.
Ardern said the Government understood this decision will have a significant impact on the economy.
"However, such temporary measures are essential if we are to avoid the worst of what we are now seeing overseas."
She said regions like Europe were going through a "tidal wave" of Covid-19 cases.
Ardern said she has become increasingly concerned that visitors to New Zealand have not been adequately self-isolating.
This is despite Government threats to deport any visitors who don't comply with the rules.
"That is an unacceptable risk that we must end," she said.
She said that at no time in New Zealand's history has a power like this been used – "I recognise how extraordinary it is."
The goal is to break Covid-19 into "small waves" of cases, rather than the "overwhelming number" experienced in other countries.
Ardern wanted to make it clear that the border shut-down applied to people and not products.
The rules would not affect freight coming into New Zealand, she said.
"Our shelves will be stocked – there is no reason to panic-buy."
She urged New Zealanders to "have a plan, and prepare" in the knowledge that supermarkets will continue to have food on shelves.
Cabinet decided on the border shut-down when it met at 4pm this afternoon.
Ardern told media she contacted Australian Prime Minister Scott Morrison after the decision was made.
Moments before the decision was announced, Australia also closed its borders to non-residents and citizens.
Speaking to media, Morrison said: "We [NZ and Australia] have worked today to align what we are doing,"
But Ardern said Morrison's decision had no influence on her decision.
She did not notify any other world leaders of the Government's plans.
More than 600,000 New Zealanders live in Australia, and Ardern said they should not travel.
"While we do not have community transmission, it is in Australia. It is in everyone's interest that they stay put."