Seven new cases of Covid-19 have been reported in the community in New Zealand today, with all but one already linked to the cluster responsible for all the previous community cases.

Health Minister Chris Hipkins and Director-General of Health Ashley Bloomfield are providing today's Covid-19 update.

Dr Bloomfield said there were no new cases to report from managed isolation.

The one new case that remains under investigation is in addition to the one case yesterday that is being investigated.

"But in both cases we feel quite cofident that they will be linked to the outbreak."

Yesterday Prime Minister Jacinda Ardern announced that Auckland will remain in alert level 3 while the rest of the country remains at level 2.

The current alert levels will remain until 11.59pm on 26 August, but will be reviewed on 21 August.

There were 12 new Covid-19 cases announced yesterday and one probable case.

Today epidemiologist Sir David Skegg told RNZ's Kim Hill that New Zealand needs to dramatically improve its pandemic response if it is to avoid going in to lockdown every time there is an outbreak.

And Hipkins told Kim Hill that in reviewing the lockdown next week, they will be looking at the spread of the virus outside of Auckland, cases without a clear link to the existing cluster, and finding a likely source of the cluster.

They would also be looking at genome sequencing and results of testing on border staff, he said.