Auckland has gone another day, with no more community cases of Covid 19.

Associate Health Minister Peeni Henare says he hasn't been advised of any further cases overnight -- beyond those confirmed on Sunday night.

Auckland is now on day five of its Level Three lockdown, while the rest of the country remains at Level Two.

Covid-19 data modelling expert Shaun Hendy told Mike Hosking it was an excellent sign that none of the tests taken in the community had come back positive this week.

He said if there were no new community cases today and tomorrow, the Government would more than likely reduce alert levels.

New Zealand had proven to be "lucky" this time round.

He said there was a sting in the tail of the initial outbreak, which a three-day lockdown not enough to close. This lastest seven-day lockdown was the Government making absolutely sure to shut it down with confidence.

He said the UK variant was challenging to curtail but it appeared shorter, sharper lockdowns to control outbreaks were worth it in the long run.

"It was a good sign yesterday that none of the very large number of tests processed on Tuesday came back positive. That's an excellent sign and we'll be hoping we see the same thing today."

There were a number of potential exposures to a positive case last week and so far it appeared there had been no infections as a result.

"The one thing we know with this B.1.1.7 vairant, you really don't want to let it get out of control. It spreads more rapidly and does take a lot of work to control."

He said it was a super-spreading virus so although four out of five infected people would only affect household or very close contacts, the fifth person would spread it far and wide.

He hoped the student who attended classes and went to the gym while infectious for up to a week was not that fifth person.

Hendy said one of the major lessons from this outbreak centred on the difficulties of contact tracing in a school community.

"It's very different to a workplace, for example, or even a retail environment. You've got a lot of casual encounters, you've got kids changing places and classrooms. I think that actually presents a really big challenge.

"If we have a situation like this at a school or a university in future we're just going to have to be that much better at our game."