The Government and Health Ministry aren't giving up on finding the original source of the current Auckland Covid-19 cluster.
There are now 177 cases making up the cluster, with 55 active.
Director-General of Health Dr Ashley Bloomfield told Mike Hosking they're keen to find out where the outbreak started.
He's confident it wasn't a case simmering in the community, and believes it must have come through the border somewhere.
"The question is whether it happened through a casual contact at the airport or port, or whether it happened at a managed isolation facility."
Health authorities are backing Auckland University's Covid-19 modelling.
Jacinda Ardern says modelling for the Ministry of Health suggests around a 25 percent chance of Covid-19 cases moving outside the Auckland region.
Dr Ashley Bloomfield says the percentage will continue to drop, if case numbers decrease in the coming days.
He says the modellers put in a range of assumptions - around travel patterns, the number of cases in Auckland, and different likelihoods of the virus spreading.