There's still hope Auckland could drop alert levels in the not too distant future, even with new Covid-19 cases appearing in the community, a top epidemiologist says.
The Ministry of Health announced a third straight day of 20 new community cases of Covid-19 on Monday, a welcomed drop down from the over 80 cases seen daily earlier in the outbreak.
Professor Michael Baker noted it was "very good news" that New Zealand's Delta variant outbreak was seemingly on the decline.
"It is very good news for a number of reasons; firstly, it's a sign that we're getting on top of this outbreak."
He added that the main cause of concern for Auckland, as it remains in Alert Level 4, is the emergence of "mystery cases".
Baker cited the news that an elderly patient at Middlemore Hospital in Auckland tested positive for Covid-19 on Sunday.
After showing up at the hospital's emergency department on Saturday, the man ended up sharing a room with three others on the surgical ward.
He wasn't tested for Covid-19 until the following day.
Baker noted that for Auckland to move down to Alert Level 3 safely, health officials need to be able to track down cases and link them to the outbreak.
"We want to see no more mystery cases," he told Breakfast.
"In fact, Auckland could move down with still come cases if they're known contacts of other cases."
To date, there have been more than 38,000 close contacts identified by health officials, with 86 per cent tied to the Auckland cluster.
The risk of unknown cases in the community is one of the primary drives behind the new rules around mask wearing for most outside of Auckland.
He says the Delta variant is more infectious than the initial strain seen in other outbreaks in New Zealand, with a higher chance of being spread through "fleeting" exchanges.
"They'll be firing out these aerosols that can fill a whole room, and that's why masks are going to be the key protection we have indoors for the medium term at least."
Yesterday, Prime Minister Jacinda Ardern announced that New Zealand outside of Auckland would drop to "Delta Level 2" at 11.59pm Tuesday.
Part of the new regulations introduced, other than mask-wearing at indoor spaces, was the announcement that capacity at venues such as bars and cafes would be halved to 50 people at one time.
Baker says this is to limit the number of people who would contact someone if a person with Covid-19 visited a venue.
"We've seen what can happen in Auckland; we don't want to have a repeat of that in any other part of New Zealand."
He'd been avocating for a two-tiered approach to Alert Level 2 so New Zealanders could gradually ease restrictions like what is seen between the shifts of Alert Level 3 and 4.
"We have this one-size-fits-all at Level 2, but I think there's room for improvement there."