Aucklanders are being asked to not panic by Mayor Phil Goff amid revelations there are four new cases of Covid-19 in New Zealand and the country's biggest city is headed into a level 3 lockdown.

As of noon Wednesday, Auckland will move to level 3 for three days until midnight on Friday. The rest of the country will move to alert level 2 at midday tomorrow - until midnight on Friday.

Goff tonight was calling for calm and patience as another lockdown looms over the city.

"I understand that people are probably feeling a little bit scared, a little angry and a little confused right now. None of us wanted to go back into a lockdown, but we always knew this was a very real possibility," he said.

"I am urging Aucklanders to come together like we did last time to stamp out community transmission. Please remain calm, please do not panic buy and please follow the lockdown rules.

"Please follow Ministry of Health advice around good hygiene practices and social distancing. If you have symptoms, please make sure you get tested and avoid contact with others.

"We beat community transmission once and we can do again, but that requires all of us to work as a team.

"Like last time, more details will be forthcoming over the next little while, so please keep updated through news channel and official government websites."