Prime Minister Jacinda Ardern says her Coalition government has decided Auckland will remain in Alert Level 3 and the rest of the country in level 2 for 12 more days until midnight on Wednesday, August 26.
It comes after an outbreak of community transmitted Covid-19 cases were found in Auckland this week.
"We have identified 29 cases at this stage linked to one cluster centred in Auckland. One other case linked is still being investigated," Ardern says.
The earliest case linked to the Auckland outbreak was a worker at the Americold cool store in Mt Wellington on July 31, Ardern says.
There is no clear connection the case has that could be linked to the border or anyone in managed isolation or quarantine facilities at this stage, she says.
Ardern says 12 more days of lockdown will allow the outbreak perimeter to be identified and isolated so that Auckland will be able to move to level two in confidence.
In the past 58 hours, Ardern says more than 30,000 tests have been taken around the country and 38 people linked to the Auckland cluster are in managed quarantine hotels.
Her Cabinet will review the situation on August 21.