It's still early days with the Covid-19 Omicron variant, but the prime minister says our border settings have served us well so far and she's confident that so far, they are appropriate.

Travel from nine southern African countries have now been banned to curb potential spread of the new Omicron coronavirus variant, after it was first identified in South Africa.

Ardern told Morning Report the country's border settings allowed for the ban - but there is also a layer of protection in the MIQ system.

The government has moved swiftly in response to Omicron, she says.

"We already have a system where if we deem countries to be what we call very high risk, that we can move into a requirement that we reduced down who's able to enter from those countries, but also then of course make sure that they're going in for a full 14 days (MIQ) and undertake the testing on day one, three, six, nine and 12.

"So that's what we've very quickly being able to move to ... we haven't, you know, made the wide sweeping changes to our borders that we've seen in many other places and that is serving us well, and it's because we've always been quite cautious about any changes and settings that we've made.

"At this stage - and I'd say this for Australia and more broadly stage it is very early days … but because all travellers that come in are coming into our facilities, and if they test positive, we sequence that, we'll know whether or not they are positive for this particular variant, then we are confident at this stage that the settings are where they need to be."

"If we see more widespread cases in those countries then we will consider whether they need to be classified as very high risk countries," says Ardern.

"All the way through this pandemic of course we've asked travellers to be, you know, to be really thoughtful about their travel. We we're not at the stage announcing changes to our border plans, but we will always consider the most up-to-date evidence and advice and take those steps, which are precautionary.

"We've always had settings that will last us the distance. We're not scheduled to make any changes broadly beyond Australia to home isolation until February.

"If we have concerns that there will be something we need to change, we'll signal that with as much advance warning as we can, but it is too early to say at the moment.

"(It is) Interesting to me that the World Health Organisation is suggesting that we will have some further evidence around transmissibility, and the degree to which this creates more severe or possibly more mild illness. At this stage we just don't yet know.

"We do know that the doctors in South Africa are part of finding this new variant have thus far reported milder symptoms in younger patients, but again, we will see what the evidence bears."

Traffic light system

Ardern says nowhere in the country will move to the green setting in the traffic light system on Friday when it takes effect for the whole country.

"We're in a period of transition, so this first suit of decisions will be a little bit different over the summer period than what they may be in the future because we're transitioning, we are still trying to manage an outbreak and make sure that we're restricting down any potential spread, so that will be a factor in our minds for these decisions."

The government would take a "regional approach" for the settings "strictly for the purpose of the ease of setting the regulations we tend to use local government boundaries to make that easier".

Vaccine certificates

Ardern says all businesses operating with vaccine passes are obligated to check someone is vaccinated.

"What we're not so specific about is do you have to use the verifier app to do that, or could you just look or ask for a different form of photographic ID? How you check we have some flexibility around."

She don't think that created risk that there could be fake certificates.

Maybe how you cheek we have some flexibility around.

"Look, say you're in clubbing, you're taking in patrons at the door and you want to check that someone is over the age. It might make more sense for you to see both the pass and photo ID, and that is perfectly acceptable.

"What we're wanting to make sure is that we're not requiring a third thing. You do have to check though, but how you cheek has some flexibility around it."

-RNZ.