Cabinet has agreed to a change in Covid-19 alert levels for both Auckland, the centre of the current Covid-19 outbreak, and the rest of New Zealand this week.

The alert levels were reviewed by Cabinet today, and no new cases of Covid-19 were reported in New Zealand.

Here's what you need to know about the change in alert levels:

Level 2 guidelines for Auckland

Auckland has operated at tailor-made "alert level 2.5" since 31 August, as a step down from level 3 restrictions.

The city will now move down to level 2, with eased restrictions on gatherings, at 11.59pm on Wednesday.

That level will be in place for 14 days, with Cabinet set to review those settings again on 5 October.

"This run of effectively seven days without any additional cases as part of this Auckland outbreak gave us a sense that it was safe to move to an upper gathering limit consistent with the usual alert level 2 arrangements," Director-General of Health Ashley Bloomfield said today.

The change in levels means gatherings of up to 100 people will now be allowed in Auckland.

Prime Minister Jacinda Ardern said despite the drop in levels, Aucklanders needed to remain vigilant and stay home when sick and get tested, "even if it is just a sniffle or a cough", and continue to scan or keep a record of where they go.

Face coverings will continue to be mandatory on public transport and are also required on flights going through, to, or from Auckland.

In order for Auckland to move to level 1, it would require the city to maintain its current downward trajectory of cases, Ardern said.

"Essentially Auckland needs more time. Whilst we have reasonable confidence that we are on the right track there is still a need in Auckland for that cautious approach, this was the center of the outbreak and that is why that caution is required here."

She said if Auckland remained on track, Cabinet would consider moving alert levels from 7 October.

Level 1 guidelines for rest of New Zealand

The rest of the country will move down to alert level 1 from midnight tonight.

Ardern said this move was possible because there had not been regional spread of the virus outside of Auckland. However, at alert level 1, there is still a risk of Covid-19 returning to the community, according to the Ministry of Health.

Staying at home while sick remains important at level 1, because the risk of the virus spreading in the community is greater when there are no restrictions on going out.

The public are encouraged to continue tracking their movements and contacts, either by using the NZ Covid Tracer app, or keeping a diary.

While face masks are not compulsory at level 1, they are still recommended in settings where physical distancing is more difficult.

The Ministry of Health also recommends being prepared by having a supply of face coverings for everyone in a household.

Ardern also said there were some large scale events scheduled for the rest of the month, outside of Auckland.

She said MBIE had been asked to reach out to the organisers of these events to make sure they were using the Covid tracer app and were keeping good details of attendees.

"There is a code of conduct in place that we will be asking those large scale event organisers to be abiding by as well," she said.