Minister of Health Chris Hipkins says it is not known who patient zero from the latest cluster is but genome testing suggests the strain of COVID-19 originated in the United Kingdom or Australia.
"At this point we don't know where patient zero is because we haven't been able to identify how the original family ... contracted COVID-19 in the first place.
"That's why we've had to take the reasonably strong measures that we have taken because until we can run that down, we need to be extra cautious."
Asked what was taking place to find that source, Hipkins said: "We are doing everything and we are tackling this from both ends in terms of going back through all of the contacts that the original family have had and continuing to test and contact trace and test and contact trace all the way through.
"We are also approaching it from the other end. We are looking at areas where there may have been risk so looking at the border - all border task are being tested - we set a goal to test all staff working at the border within 72 hours, all of the staff working in managed isolation and quarantine just so we can discount that as a possibility.
"We are trying to gather as much information as we can in as quick a period as we can so we can piece this puzzle together.
Asked what the working theory was for where it came from, he said there was not one but multiple different scenarios. "I would not rule any of them in or out."
Genome testing of the strain of COVID-19 contracted by the family suggested the strand originated in the UK or Australia, but it was not clear how it ended up in Auckland.
"We are a little bit cautious about that. The results... aren't necessarily at the level that we can be certain."
The newly infected community transmission cases were moving to the Jet Park hotel but would not impact on the capacity for managed isolation and quarantine, he said.
"We've got the ability if we really end up getting stretched to set up a second quarantine facility ... most likely at one of the managed isolation facilities we have got."
As for the resthome facility in the Waikato where people were being tested, it is in Morrinsville. Hipkins said everyone who needed to be tested at the facility had been, and results would be available tomorrow.
Asked what modelling showed as far how much the current cluster could spread, Hipkins said he had not received a "working model with some upper numbers".
"We know that at the moment all these cases are within a cluster, they are interconnected and that does, to some extent, draw a ring around it."
As far as contact tracing around the cluster, "several hundred" had been reached so far, he said.
"I haven't got the most exact number but around 400 was the last number I saw a few hours ago."
The "finder service" - physically looking for a contact - had only been deployed for one person, Hipkins said.
Swabs had not come back from testing at Americold. He hoped for results by the end of the day.
Asked if lockdown length could follow the infection and incubation cycle like the first lockdown, he said: "I think that's a decision for [Friday]".
Spread of the virus, the number of active cases, the number of new cases each day and the number of overall tests and their results would all be considered when contemplating extending the lockdown.
Hipkins also met with the National Party's health spokesperson, Dr Shane Reti, Thursday afternoon.
"We had a very good discussion. I think the feedback he gave me was he was very satisfied with both the work we were doing and the quality of the briefing.
"I think they wanted to understand what we were doing, they wanted to understand the issues that we were addressing, basically I think they wanted a bit of an overview about how the contact tracing was going. I think we gave them some reassurance that we are doing everything we need to be doing, they asked a few questions, it was a very useful conversation."
RNZ
