Officials are looking at the possibility that workers on a freight ship or at the port may have spread the infections.
The 12-day lockdown extension means that, in Auckland, public places — such as libraries, museums, cinemas, food courts, and playgrounds — must be closed and people work from home when possible.
Supermarkets and petrol stations can open, but other “close contact” businesses must shut.
Prime minister Jacinda Ardern said the decision to extend the restrictions was “in keeping with our cautionary approach and New Zealand’s philosophy of going hard and going early”.
A man in his 20s has died of coronavirus in Australia, the country’s youngest victim.
He is among 14 people in Victoria to have died in the past 24 hours,
North Korea’s leader Kim Jong-un has lifted a lockdown in major city Kaesong near the border with South Korea where thousands had been quarantined over coronavirus fears.
Russia reported 5,065 new coronavirus cases today, bringing its nationwide tally to 912,823, the fourth highest in the world.
