Thousands of people attend a concert by the band Six60 on Saturday, Feb 13, 2021, in Wellington, New Zealand. New Zealand’s largest city of Auckland is being placed into a three-day lockdown Sunday following the discovery of three unexplained virus cases. (Photo: AP)

New Zealand Prime Minister Jacinda Ardern ordered the city of Auckland into a three-day lockdown on Sunday after three Covid-19 cases emerged in the community.

The city's 1.7 million residents were told to stay at home from midnight, when the level-three lockdown begins, with schools and businesses to close except for essential services.

Ardern said the lockdown is "just in case it could be one of the more transmissible strains of COVID that we need to act with a high degree of caution around."