Epidemiologist Michael Baker is warning the latest burst of COVID-19 is more similar to the August 2020 cluster than most border breaches.
Prime Minister Jacinda Ardern and COVID-19 Response Minister Chris Hipkins announced on Sunday that New Zealand had recorded three new cases of COVID-19 in the community.
The three people are all from the same family but had visited several locations in south Auckland and New Plymouth before testing positive.
As a result, Auckland was put into alert level 3 lockdown for three days, while the rest of the country moved to alert level 2 from 11:59pm Sunday.
The University of Otago's Professor Michael Baker told The AM Show on Monday he doesn't know if the three-day lockdown will be enough to contain the virus.
"It will give us time to work out the extent of the outbreak and of course the reason for going hard and going early with this one is that there could be other cases in the community," he said.
"Although the mother in this household does work at a business related to the border, she doesn't have direct contact with travellers or work in an MIQ facility. There isn't an obvious mode of transmission in this outbreak so that could mean there are other cases in the community that have been detected."
Prof Baker warned these new cases aren't likely to be another small border breach like the Northland community case.
"We do have a failure at the border every couple of weeks or so and generally it's just a single staff member infected or someone who got infected in an MIQ facility and have brought it into the community," he said.
"We know these have been very well managed with tracing and so on but this is more like the Auckland August outbreak. Hopefully, it will be much smaller but that supports why there is a very vigorous response. I think it is totally the right thing to do."
Auckland was put into a level 3 lockdown in August following new cases of unknown origin.
The cluster became the biggest in New Zealand, with 179 cases recorded, according to the Ministry of Health.
Baker told The AM Show New Zealand should put more emphasis on border protection to decrease the risk of COVID-19 getting into the community.
"We have always had people coming and going and I think we will continue that. It's just about turning down the tap on the number of infected people arriving from some parts of the world where there is a lot of active transmission. What I'm hoping is we will put more effort into the pre-departure arrangements for people coming back to New Zealand."
He said the Government needs to look at what can be done at each point of the arrival process to make it more secure.
"I think we have to at least for the next few months as the pandemic is still very intense overseas and we have these more infectious variants."