One of New Zealand's leading Covid-19 modellers says it's up to Aucklanders whether they'll move to Level 2 or shift back to Level 4 in a fortnight's time.
Shaun Hendy spoke to Breakfast on Wednesday morning follow Auckland's move to Alert Level 3 overnight, saying the shift came with risks but they were calculated.
"[Elimination] will be more difficult in Level 3, just because we have more contacts and more people going back into the workplace so more chances for the virus to spread.
"However, case numbers are down to the level where contact tracers could wrap this cluster up," Hendy said.
"We could start to think at the end of this two-week period about Level 2, but it's definitely going to require us all to play our part and take Level 3 seriously."
Hendy said there were multiple scenarios that could play out at Level 3 for Auckland, including a slow incline in case numbers as approximately 300,000 Aucklanders return to the workplace.
If that were to happen, Hendy said Auckland could face a lengthy stint out Level 3 - or worse.
"[A rise in daily case numbers] would tell us that we'd probably have to have an extended Level 3 period or maybe a shift back to Level 4," Hendy said.
"We just don't want to end up in situation like New South Wales or Victoria where we're recording 1000 cases a day - that's the kind of outbreak that would really damage our healthcare system."
A return to Level 4 would be a result of a large spike in unknown cases, Hendy said.
"It depends on how quickly case numbers grew but we might have to shift to Level 4 if numbers grow substantially," he said.
"Then, I think we'd be really reliant on our vaccination programme [to beat the outbreak]; once we get up into the high 80 or 90 per cent of the population, that will have a real affect on case numbers and should allow us to bring any outbreak under control but that won't be until November."
Hendy added the best-case scenario for Auckland in contrast is achievable too.
"Two weeks could be enough to close this cluster out," he said.
"The number to watch is the unlinked cases that are turning up which has slowly trended down, so although the number of unexpected cases has slowly trended down.
"We want to see that go to zero and have many days of zero - that would tell us that we've contained the cluster and it's no longer growing in places we don't expect it to and that gives us a great chance of pushing out of Alert Level 3 in a fortnight."
Hendy said his models are being effected positively by the uptake in vaccination as well as a more prominent use of masks in public.
"We're dealing with Delta this year so we absolute need all of those things.
"Even though numbers have been fantastic - it has been amazing to see the response of Kiwis to the vaccination programme and I'm very proud of how we've responded to that - but it will take time for us to see all the benefits of that."