COVID-19: Jacinda Ardern uses Australia as example of what not to do in lockdown

Prime Minister Jacinda Ardern is urging New Zealanders to stick to the COVID-19 lockdown rules, saying Australia is a perfect example of how things can go wrong.

On Tuesday Ardern announced Aotearoa will enter COVID-19 alert level 4 at 11.59pm after a 58-year-old man contracted COVID-19 with no link to the border.

While genomic testing will not be returned until Wednesday morning, Ardern says it's safe to assume he has contracted the highly transmissible Delta variant - and that assumption has shaped her decision to put the country into the highest level of restrictions. 

When asked about people who might be tempted to defy lockdown restrictions, Ardern said they only need to look to Australia to see how that could impact New Zealand. 

"We just need to look overseas and see what has happened there because of some of the decisions of those people covered by those lockdowns who don't follow the rules - it has extended the period of time they're there."

Australia is currently in the grips of a vicious COVID-19 outbreak which has seen multiple states enter weeks-long restrictions. 

In New South Wales, cases in their hundreds are being recorded daily and hospitalisations are skyrocketing. 

"We've seen what's happened in Sydney - we don't want that here," said Ardern.

She added previous lockdowns have seen good compliance - bar a few people who spoil it for others - and her message to Kiwis is to "do what you've done before".

"We want this lockdown to be short and sharp, rather than light and long."

New Zealand will be at COVID-19 alert level 4 for at least three days - with Auckland and the Coromandel expected to be lockdown for seven.

Everyone must stay home, with the only exceptions being shopping for essentials, attending essential work or seeking urgent medical attention.

People are permitted to exercise outside - but they must avoid other people, and stay local.