Auckland's lockdown lite will not lift early and will remain at least until the end of Wednesday.
Prime Minister Jacinda Ardern said Cabinet would meet on Monday to decide whether the current alert levels for the city and the rest of New Zealand need to be changed.
Auckland is scheduled to be in alert level 3 and the rest of the country in level 2 until 11.59pm, August 26.
"At this stage, we need to stay the course," Ardern said.
She said there were encouraging signs and there was no need to make the settings more restrictive - but they would not be eased ahead of the current schedule.
Genome sequencing has now also linked the St Lukes worker to the existing cluster, and they may have caught Covid-19 by sharing the same bus ride as another positive case.
One thing Cabinet will have to grapple with on Monday is whether travel restrictions in and out of Auckland should remain if the city was moved to level 2 after Wednesday.
Ardern's announcement followed 11 new Covid cases being revealed today, nine in the community and two in managed isolation.
Five of the new cases were linked to South Auckland churches, and of 223 identified close contacts, 170 have been tested.
Alert level 3 - which Auckland has been in since Wednesday last week - had played a critical role in looking for the outbreak's perimeter and cases had been found early, Ardern said.
"There is nothing to suggest we need to change our course and certainly nothing to suggest we need to elevate alert settings."
What will influence Monday's lockdown decision
Ardern said there were several factors to consider on Monday, including trends in the cases and their transmission, contact-tracing capacity, effectiveness of border measures and the health system's capacity.
Broader factors include the effects on the economy, at-risk populations, levels of public compliance and the ability to operationalise alert level settings.
Monday's decision will also be based on the director general of health Ashley Bloomfield's advice, and he will consider case numbers, and the pattern of those cases.
He will also look at modelling from Professor Shaun Hendy's team about what might happen under different scenarios.
There have been 170,515 tests since our current alert settings began.
Contact-tracing was meeting the standard of contacting 80 per cent of close contacts within 48 hours, Ardern said.
"New Zealand is among a small number of countries that still has a low rate of Covid cases, and a low death rate," said Ardern, making a comparison with the United States.
It may have been a subtle reply to US President Donald Trump, who has repeatedly claimed New Zealand's Covid outbreak was out of control.
Asked about Trump's comments about New Zealand's Covid cases, she said anyone can see the different Covid numbers between the US and New Zealand.
There have only been two arrests under alert level 3, she said, and Google data showed Aucklanders were moving about less than the last time the city was under the same restrictions.
What happens in future outbreaks?
The resurgence plan, Ardern said, meant level 3 wouldn't always be needed in future outbreaks.
This one was different because South Auckland had a higher population density and many social gatherings, she said.
The Rydges worker case
The PM said the Rydges maintenance worker who tested positive showed how the system should work, where genome sequencing pinpointed a link to an overseas arrival and close contacts were quickly isolated.
The Rydges case is the only case outside of the cluster, which is now 88 cases, meaning there are a total of 89 cases in the community.
The cluster had many possible origins, and was highly unlikely to be linked to the first outbreak in New Zealand, Ardern said.
It hasn't been linked to any of the strains on record so far, and questions about possible interactions with border-facing workers or overseas arrivals haven't shed any more light.
Nor have surface investigations at Americold.
"We may not find all the answers for this cluster," Ardern said.
But as long as the cluster is contained, restrictions can be lifted.
St Lukes worker may have caught Covid on bus
The St Lukes mall worker may have been on the same bus as another positive case, Bloomfield said, which underlined the importance of wearing a mask on public transport.
Yesterday the case was thought to be unconnected to the cluster and possibly a new strain, but this morning it was linked to the cluster through genomic sequencing.
Bloomfield said bus card data was helping to see whether the St Lukes case was on the same bus at the same time as another positive case.
"This bus journey, the morning of August 12, was just before Auckland went into alert level 3. That's the value of having that wider restriction on movement."
That means even if there was infection on the bus, other people on the bus should have been at home since the journey.
Ardern said a discussion has been had about having QR codes on buses, but the Hop card in Auckland already provided that data.
Other cities didn't have the same data for bus cards, and Ardern said tracer apps were being looked at in those cities.
Bloomfield did not have details about where the bus was going to or from.
Eight people in hospital
Eight people are receiving hospital-level care for Covid-19 - two in Auckland City Hospital, one in North Shore and five in Middlemore.
One person at Middlemore remains in ICU.
One Covid-positive person in Waikato was hospitalised but no directly because of Covid-19.
There are 143 people linked to the cluster who have been moved into the Auckland quarantine facility, including 70 who have tested positive.
New Zealand has had 1315 confirmed cases, and has 105 active cases.
There were 15,714 tests conducted yesterday.
Bloomfield said testing border-facing workers had almost been completed, and a second round would be held. They would be regularly tested going forward, he added.
That plan, which the Government had thought was already implemented, was still being finalised.
Ardern thanked the efforts of New Zealanders but especially Aucklanders and those who had been tested.
"We would not have got in front of this cluster without them.
"There is no room for division when it comes to fighting Covid.
"We have made good progress. Unlike our first outbreak we are not dealing with multiple clusters."
How to wear a mask
Bloomfield showed his homemade mask to illustrate how people can make their own. It was made by the mother of one his son's friends.
"Homemade masks can be washed and reused."
Bandanas and scarfs can also be used, he said.
Bloomfield demonstrated how to properly fit his mask and quipped that it wasn't hard to fit it over his ears, but he had issues with his glasses fogging up.
Mosque shooter sentencing
Asked about the March 15 massacres sentencing in court next week, Ardern said she couldn't say much to ease the difficulties for families attending the case. She hadn't decided whether to watch the sentencing.
Bloomfield said some people had been granted exemptions to travel out of Auckland to attend the sentencing, but none from managed isolation facilities.
Asked about the exodus of staff at Canterbury DHB, Ardern said there were "very clearly issues that need to be dealt with and very quickly".
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The cluster is considered to have started from person-to-person infection following results showing infection from Americold surfaces - in Auckland as well as in Melbourne - was unlikely.
The Rydges maintenance worker may have caught Covid-19 after touching the same elevator button minutes after an infected traveller was in the lift.
Auckland went into level 3 lockdown and the rest of New Zealand fell into level 2 at noon on Wednesday last week.
A higher, level 4 lockdown has been ruled out on the basis of the relatively few cases so far.