Covid-19 data modeller Professor Shaun Hendy has told TVNZ1's Breakfast that whether or not Auckland moves up to Level 4 or stays at Level 3 today will likely depend on two factors.
Professor Hendy, from the University of Auckland, said it would depend on whether a link between the cool store facility and the border can be found, and whether or not additional clusters are identified.
Professor Hendy said the first and only cluster identified so far - linked to a man who works at Auckland cool store Americold - now extends "right across the city" due to Auckland's nature of being quite a distributed city.
He said his opinion is that there is some kind of link between the cool store worker and the border which hasn't been found yet.
"I'd probably rate that still as the most likely source, but having said that, we haven't found a direct connection," he said.
The best-case scenario today was that a link between the cool store facility and the border was found, and that no further clusters were identified, and in that case it was likely the restrictions in Auckland would stay at Level 3, he said.
The worst case scenario was that no link could be found and further clusters were also found, in which case Level 4 was likely.
Professor Hendy said it was possible, if the infection had been undetected for some time, that there were up to 100 current cases of Covid-19 circulating the community.