Prime Minister Jacinda Ardern is reminding New Zealanders there are "repercussions" for breaking the Government's COVID-19 rules around testing and isolating. 

The Ministry of Health reported a new community case of COVID-19 on Friday, already in quarantine and linked to the existing Papatoetoe High School cases. 

The new case defied the expectation to stay at home and isolate by working at KFC Botany Downs earlier this week, meaning people who went there between Monday 3:30pm and Tuesday 12:30am need to self-isolate and get tested. 

The Prime Minister said on Friday the KFC worker "should have" stayed home, and she's calling on all the people who need to self-isolate and get tested to do the right thing. 

"Ultimately, we're asking now of course now that we're dealing with the fact that that situation arose, for everyone who may have come in contact to do the right thing, to make sure they're isolating and make sure they're testing," Ardern said. 

"That is how the rest of the country is able to stay at level 1 with all of their freedoms. They're paying a price for everyone and doing the right thing for everyone. 

"No question, like everyone I was frustrated, but at the same time one of the things we need is an environment where people can feel like even if they've made the wrong choice, even if they've gotten tested later than they should've, they still do what we need them to do."

Ardern said there the Government can clamp down on those who defy the rules, thanks to special powers written in section 70 of the Health Act. 

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"If there is a section 70 order, of course they are obliged. We actually have some legal footing for that and so there are repercussions," Ardern said. 

"But actually, repercussions aren't what we all want. We want people to do the right thing because that's what keeps everyone safe. That's how the team of 5 million have been so successful to date."

Ardern said she's confident the Ministry of Health's contact tracing and testing abilities will keep Aucklanders safe amid anxieties about an alert level change. 

"This is a situation where we know the source of the cases, we know where there may have been contact with others - contact tracing and compliance here is critical," Ardern said.

"We can reach out, tell people who might be at risk, get them home and isolating tested, and that is a critical part of our response and our ability to stay level 1.

"The other thing I would add: there are many people who in this particular scenario that are being treated as those close-plus contacts so they haven't had necessarily one-to-one. But we are asking them to isolate and be tested. 

"We're going further than we usually do and that's for the very reason that it leaves the rest of the country able to stay at level 1."