Auckland mayor Phil Goff says he is not underestimating the impact of another lockdown will have on people's lives and businesses around the city.

The Super City has plunged into a third lockdown after a father, mother and daughter from South Auckland tested positive for Covid-19.

Prime Minister Jacinda Ardern said the Government is asking Aucklanders to "stay home" and work from home where possible.

Deputy mayor Bill Cashmore said playgrounds, swimming pools, libraries, park benches, basketball courts and customer service centres and other public venues will close. Essential services, like rubbish collections and public transport will continue.

"New cases of Covid-19 in the community was something none of us wanted to happen," Goff said yesterday.

"However, we always knew there was a risk given what we have seen overseas."

"We know from experience that quick action to impose restrictions is the best way to stamp out the virus," Goff said.

He said he would work with the Government on support the city needs during and after the lockdown to continue the recover.

Covid has already cost Auckland Council $1 billion in lost revenue. Central city businesses have been hit particularly hard as people work from home and due to the loss of overseas tourists and international students.

Goff said Aucklanders have more experience than anyone else in the country in dealing with lockdowns.

"We know what to do to stop Covid-19 from spreading and we will do it again this time," he said.

Goff said this is a good time to remember that border workers are doing an amazing job in trying to keep our city safe while doing essential work.

"They are the most vulnerable to infection and we owe a debt of gratitude to them. It's important to for all of us to remember that this not anyone's fault and compassion goes a long way during these times.

"I am urging everyone to follow Ministry of Health advice around good hygiene practices, social distancing and using the NZ Covid Tracer app. If you have symptoms or you have been at locations at the time they were visited by the cases, make sure you get tested and avoid contact with others."