All of New Zealand will go into a snap three-day lockdown from 11:59pm after confirming one case of COVID-19 in the community.
The case was confirmed in the most populous city, Auckland, earlier today, and that city and the Coromandel Peninsula will be in lockdown for seven days.
Prime Minister Jacinda Ardern said authorities could not confirm yet whether the case involved the Delta variant, but the potential risk meant they must act quickly.
"While we know that Delta is a more dangerous enemy to combat, the same actions that overcome the virus last year can be applied to beat it again."
Under the country's toughest level 4 lockdown rules, schools, offices and all businesses will be shut down and only essential services will be operational.
"We have made decisions on the basis that it is better to start high and go down levels rather than start too low, not contain the virus and see it move quickly," Ms Ardern said.