Auckland microbiologist Dr Siouxsie Wiles has revealed more information on how two women from the UK were able to get into New Zealand and travel around with Covid-19.
Yesterday it was announced New Zealand has two new cases of Covid-19, both of which were linked to arrivals from the UK.
It is now understood one woman had asthma, which may have masked her Covid-19 symptoms, and that timing played into their early release from quarantine.
The women, one in her 30s and the other in her 40s, had arrived in New Zealand together on June 7 and stayed in managed isolation in a hotel in Auckland.
They were permitted on compassionate grounds to travel to Wellington in a private vehicle on June 13 to see a parent who was ill and has since died.
Yesterday's dual diagnosis broke a 24-day streak without any new cases, and a seven-day streak without any active cases in the country.
People have slammed the border controls for letting the women out of isolation early and without being tested, but this morning on TVNZ1's Breakfast Dr Wiles explained some reasons that led to the women being released.
Earlier on Breakfast, National Party leader Todd Muller said it was "appalling" the women were allowed out of quarantine early without being tested, and he slammed the border for "being managed in a shambolic way".
However, Dr Wiles said border controls were "an incredibly complicated thing" and more complex than people might think, with multiple agencies - including police, the Ministry of Health and public health units - collaborating.
"It's quite a difficult thing almost, and what we're seeing now is where it's fallen apart.
"I'm surprised we haven't has cases like this - not the leaving quarantine, but from the people coming into the country sooner."
The majority of people arriving in New Zealand every day are returning Kiwis or family, but some are for work. Anyone arriving from offshore is required to quarantine for 14 days at set-up isolation facilities.
"I think in this case it was a little bit around timing, around actually how difficult things have been, you know. They were in quarantine and then basically my understanding is the family member's condition worsened and so it was all very quickly done, much more quickly than a test could have been organised," Dr Wiles said.
"What essentially has happened is a little bit of sort of falling through the cracks, but it just shows how important it is that we have a good plan in place. And it also kind of shows that your plan is only ever as good as until it's tested, and then you understand where holes are."
Dr Wiles said the two women with Covid-19 did everything right, but she urged anyone with Covid-19 symptoms to be tested even if they thought it was something else.
One of the new cases had asthma, which often flares up when she returns to New Zealand, which may have masked her Covid-19 symptoms.
"We know that for us our border is our barrier, and so we have to ensure that that is plugged but also this is why we're saying to people if you get any of those symptoms that could be Covid-19, still get tested because we need to be absolutely certain that if something like this happens or somebody does end up having the virus and getting through, that we can stamp out these cases really quickly.
"What we can see now is how we have to move forward, like what can we learn from this?"