Prime Minister Jacinda Ardern says work is continuing on a trans-Tasman travel bubble, but there are implications to consider - such as how to separate transiting passengers from others.
"We have to sort things like, how do you make sure that when you've got flights coming in that you don't have any transiting passengers who are intermingling with other passengers" Ardern told Newstalk ZB.
"How do you separate out airports so those who have come from outside of one country aren't mingling with others?"
The Prime Minister said there are states in Australia that have the same status as New Zealand, with no known community transmission of the coronavirus, and the creation of a travel bubble with those states "continues in earnest".
National leader Todd Muller has been pushing Ardern to explain why the trans-Tasman bubble hasn't been established yet state-by-state, and earlier this week she said it's ultimately up to her Australian counterpart Scott Morrison.
"There are two issues at play: one, community transmission in Australia. The idea that we would open up to the entire nation right now I think is out of step with where the New Zealand public is and would threaten our position."
Ardern said the "great unknown" for countries that have greater presence of COVID-19 is what it will look like beyond the availability of a COVID-19 vaccine.
"Will we have an effective treatment down the track? What's rapid testing looking like? Because that opens up a lot of opportunities," she said. "If you have the ability to rapidly test at an airport before someone enters your country, then that changes the game considerably.
"All of the planning we can do at the moment is based on the world's current status. But I think the world will be very different in a few months' time with some of those advances."
Australia and New Zealand agreed in early May to commence work on a trans-Tasman travel bubble whereby passengers would not be required to undergo two weeks of quarantine upon arrival.
But since then, Australia has suffered outbreaks of the virus. There are currently more than 800 active cases in Australia, and the southern state of Victoria has closed the border and locked down some suburbs to contain a new outbreak.
The Prime Minister earlier this week hit out at "dangerous" suggestions to open the border after the European Union listed New Zealand as "safe" and said it would allow Kiwis to travel there without having to self-isolate for two weeks.
Ardern said New Zealand would not return the favour, and anyone who travels to Europe will have to spend two weeks in the Government's managed isolation facilities upon return.
The Government has spent the last few weeks fixing its quarantine testing botch-up. New rules were introduced on June 9 that people in managed isolation and quarantine facilities need to be tested at days three and 12, and that a negative result is required for the day 12 test before being allowed to leave.
But it appeared the policy was not being enforced, after two COVID-19-carrying sisters were allowed to leave an Auckland managed isolation facility on compassionate grounds without being tested first.
It turned out more than 2000 people had been able to leave managed isolation without a test, and the Ministry of Health is still chasing up almost 300 people who refuse to return phone calls. There are also 97 people who have refused a test.
Ardern told Newstalk ZB it can be difficult dealing with human error.
"We've got the equivalent of a small town in quarantine. It's a massive operation and human behaviour exists in all of these facilities. We are dealing with humans and we're ultimately asking them to abide by very strict protocols to keep everyone safe."
The minister in charge of managed isolation, Megan Woods, announced on Thursday that Kiwis will once again be allowed to leave managed isolation facilities early on compassionate grounds, with the change to be made as soon as next week.
Two new cases of COVID-19 were recorded in managed isolation facilities on Thursday, bringing the total number of active cases in New Zealand to 18.