New Zealand said Tuesday it will move into a snap three-day nationwide lockdown from 11:59 p.m., after reporting its first case of COVID-19 in the community in six months.

Prime Minister Jacinda Ardern told a news conference that the country will move to alert level four, its highest level of restrictions, after a 58-year-old man in its largest city of Auckland tested positive for the coronavirus earlier in the afternoon.

Prime Minister Jacinda Ardern speaks to media during a press conference at Parliament on Aug. 17, 2021 in Wellington, New Zealand. (Getty/Kyodo)

Though it is yet to be determined which strain of the virus the man is infected with, authorities must assume it is the highly contagious Delta variant and move hard and fast to stamp out the virus, Ardern said.

"Going hard and early has worked for us before. While we know that Delta is a more dangerous enemy to combat, the same actions that overcame the virus last year can be applied to beat it again," said the prime minister.

Ardern said she anticipates a longer seven-day lockdown in Auckland and the Coromandel Peninsula, a tourist destination visited by the patient, around 65 kilometers east of Auckland across the Hauraki Gulf.

This is the first case of the novel coronavirus that has been detected in the New Zealand community since February, but no links have yet been found to international arrivals or quarantine facilities, causing concern for officials that there may be unrecognized chains of transmission in Auckland and beyond.

Tuesday's move marks the first time New Zealand has been placed under its highest COVID-19 alert level since April 2020. Under the measures, citizens will be asked to stay at home, and only leave for essential reasons such as shopping for groceries, receiving necessary medical care and doing exercises, with Ardern asking New Zealanders to wear a mask whenever they leave the house.

The level four restrictions will also see schools and nonessential businesses closed, and isolated individuals will be able to nominate one other person to form a "bubble."

New Zealand has been largely free of community transmission for much of the pandemic, and has reported just under 3,000 cases and 26 deaths to date.