A Covid-19 modelling expert believes lockdown fatigue may necessitate an alert level shift in Auckland next week, even though it risks stoking Delta's slow-burning embers.

With 11 community cases announced today, University of Auckland professor Shaun Hendy says Cabinet will be forced to balance the risk of further transmission with the consequences of prolonging lockdown when it considers on Monday whether to confirm the in-principle decision to shift to alert level 3.

"You could persist at level 4 and stamp this out, I'm pretty sure that'd would be the case," Hendy said.

"On the other hand, everybody's a bit over level 4, people need a bit of light at the end of the tunnel.

"It's probably worth taking a calculated risk."

Of the outbreak's 457 active cases, eight were yet to be epidemiologically linked. Nine of yesterday's 15 cases had been infectious in the community.

Nevertheless, director of public health Dr Caroline McElnay said there was "cautious optimism" the vast majority of the outbreak had been contained.

While confident exiting lockdown wouldn't be immediately catastrophic, Hendy said relaxing restrictions while the virus circulated in the community could have consequences.

"If we're still seeing consistent community transmission then by going to [level] 3, you just give [transmission] the opportunity to speed up.

"If you're accepting that we may need to go back to level 4 in some time in October, then shifting to level 3 is a low-risk option."

Hendy said without factoring in how long Aucklanders had been in lockdown for, he would advocate against a move to level 3 until the virus had been stamped out of the community.

However, he said lockdown was a taxing environment in which to live and was concerned about compliance if lockdown continued.

He also noted elimination at level 3 was not impossible.

Infectious diseases modeller Mick Roberts said today's case information was reassuring for the most part.

"The unlinked cases are not going up, so that all looks good," he said.

"It looks like they know about the Auckland clusters, what they're doing and where they are."

However, he did acknowledge the risk posed by the Covid-positive truck driver, who was now in quarantine after recently visiting a number of locations en route to Tauranga while infectious.

"You're hoping that [the truck driver] hasn't infected anyone outside Auckland, that'd be a shame."