Epidemiologist Michael Baker is picking Auckland will stay at alert level 4 for at least two more weeks beyond the current Tuesday deadline.
But the rest of the country might hear better news on Friday afternoon from Prime Minister Jacinda Ardern, with a good chance of restrictions being eased.
The daily COVID-19 case numbers in the city continue to rise, with 68 reported on Thursday. But the slowing pace of increase - Thursday's figure just seven higher than Wednesday's - and the small number of new locations of interest since level 4 began has given authorities hope the lockdown is working to contain the spread of the highly contagious Delta variant.
"If it weren’t for lockdown, I’m sure we would have seen cases spread further," Prime Minister Jacinda Ardern said. "Lockdown is also having an impact on locations of interest. While our cases are continuing to grow, these locations of interest aren’t continuing to grow exponentially alongside them."
Auckland is currently set to be at level 4 until the end of the month, and the rest of New Zealand only until 11:59pm Friday.
"Now there's a choice about obviously the South Island, Auckland and potentially the rest of the North Island being treated differently," Dr Baker told The AM Show on Friday.
"What alert level does the South Island or part of the North Island move to? Is it directly down to alert level 3, which seems reasonable, and when does it happen? Potentially next Tuesday night, which would be two full weeks."
This should be long enough for any last cases infected by people who left Auckland before the lockdown began to be picked up, Dr Baker said.
"The whole country has been seeded with cases from Auckland - some of them have developed into cases obviously in Wellington, some people who went to the South Island obviously were just exposed. We haven't reached the maximum incubation period yet.
"The wastewater testing is negative, there's a huge amount of testing of people who have been at those places of interest and also people showing symptoms that's happened in the South Island. As long as that stays negative of course, I think we can comfortably move down alert levels. At least for the South Island, potentially for parts of the North Island."
There have been traces of the SARS-CoV-2 virus picked up in wastewater in Christchurch, but scientists said it was likely just from three cases picked up in the city's managed isolation facilities.
With transmission still happening in Auckland despite the restrictions, Dr Baker's recommending the city stays at level 4.
"We're still seeing new cases appearing, there's still transmission in Auckland - hopefully just in Auckland. It's just the sheer number of infected people, the fact some of them are still infecting large households - there's transmission there - and some of the cases are in essential workers who were out and about. That's still the weak spot with even alert level 4, which is a very tight lockdown. It still has about 10 percent of the workforce out and about. "
He said Kiwis shouldn't be surprised if the lower alert levels are beefed up to include stricter mask mandates.
"An obvious change is we need this mask mandate probably at alert level 2 as well because we know a lot more about how this virus is transmitted. It's a very good respiratory pathogen that can spread as an aerosol. Otherwise there isn't very much at alert level 2 unless you have masks required indoors."
Ardern and Director-General of Health Ashley Bloomfield will provide the latest updates on the outbreak and Cabinet's alert level decisions at 3pm.
