New Zealand's contact tracing system is far from state of the art and still needs a lot of improvement, says an epidemiologist.
New Zealand now has zero cases of Covid-19 and has reached alert level 1 - a way of life not seen in more than 11 weeks.
While professor of public health at Otago University Nick Wilson says it's a fantastic achievement for New Zealand, he would still like to see some improvements to the government's response.
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"The gaps are; wearing masks at the border, on incoming aircraft, at airports and also with our contact tracing - it is still far from state of the art," he told Morning Report.
New Zealand's contact tracing system is way behind places like Taiwan and South Korea, he said.
"We're relying on manual tracing systems, in a pretty low-quality app in most people's view.
"That's just completely unacceptable."
If there was a border-control failure and someone was still infected with Covid-19, it could trigger an outbreak, he said.
He said contact tracing would allow this to be fully controlled.
"The government has done some great work on exploring a smart card with Bluetooth technology but that is many weeks away from being introduced even if it does get to that point."
In the meantime, the government needs to be looking at other systems, he said.
Director general of health Dr Ashley Bloomfield told media yesterday that masks were not necessary at level 1.
However, Wilson believes masks should be worn at the border for absolute protection.
He said the very low chance of community transmission means wearing them in daily life, like on public transport, may not be worthwhile.
In level 4, New Zealand lost the opportunity to build a culture of mass-masking, he said.
Ardern said she does not regret the decision to not create a mask-wearing culture. "We were, predominantly, in our bubbles. We were predominantly indoors, with small ventures out and, of course, some people did choose to wear masks.
"Let's also keep in mind that the WHO is recommending that when a large number of countries are still continuing to see increasing cases."
Ardern said most people who work in contact tracing say that human responses are the most effective response, and that is what the government has scaled up.
She said while Bluetooth has been widely touted as an option for New Zealand, there were rollout problems in Singapore with that system.
"You'd have to have a large number of New Zealanders putting it on their phone, keeping it on their phone.
"What we put out was just a way to help people record where they've been. The Bluetooth option requires a very high percentage of New Zealanders to have downloaded it in order for it to have worked."