After 102 days without community transmission they are the first cases acquired from an unknown source.
The rest of New Zealand will move to level 2 at the same time.
"These three days will give us time to assess the situation, gather information, make sure we have wide-spread contact tracing," Ardern said.
Under level 3 in Auckland, people are to work from home unless they are essential workers, and stay in their bubbles.
"As we did in the early days of the virus emerging, we need to stamp it out," Bloomfield said.
People are also encouraged to use a mask "in spaces and places where it is hard to physically distance".
Bloomfield said the Covid tracer app would be essential in contact tracing, and urged people to download and use it. »