The prime minister wants quality assurance from pre-departure testing from countries where New Zealanders are flying from.
A two-week travel suspension will come into force on Sunday for flights arriving here from India, where about 100,000 cases are being recorded every day.
There are six new cases in managed isolation here today - five of those are from India, adding to the 17 recorded yesterday.
Jacinda Ardern said the government needed to be sure those travelling here are safe in their journey - and that the pre-departure testing process is robust.
"With those flights that will continue to come in before the new suspension comes in place, they will have the same level of precaution and care as we do for every flight. Keeping in mind we treat every international arrival as if they potentially have Covid-19. That's our practice and that hasn't changed," Ardern said.
Asked if the government would move those passengers - and all from high-risk countries - in the same quarantine facility, Ardern said: "Everyone is screened and so if someone is thought on arrival to potentially have Covid they may be screened to go into our quarantine facilities straight away.
"We then undertake day zero testing to provide confirmation of whether anyone further needs to go into quarantine, but we already have mechanisms we are confident in to deal with anyone coming in from either low or high risk countries appropriately".
Over the past two weeks there had been over 60 passengers arrive from India with Covid-19, Ardern said.
With about 90 active cases of the coronavirus in the country, the proportion of cases from India was "relatively high", she said.
"If that number of people from any country were coming in with Covid, that would give us cause to pause, look at mitigations to reduce that risk."
Ardern had not yet received any legal advice about extending the suspension.
"We are confident, of course, in what we have done now."
On the subject of dodgy pre-departure test results, Ardern said it was not clear if every country was running pre-departure PCR tests in the same way that New Zealand was.
"One of the things we are exploring is the quality assurance of testing regimes."
Asked if New Zealand needed its own quarantine facilities at points of departure, Ardern said that had been put to her as a potential option.
"We are exploring a range of possibilities, but given our experience here in New Zealand around how difficult infection control in facilities are, particularly when you have a large outbreak in the community, not just within facilities, I don't think we would underestimate the challenge that would exist with that."