The upper projection would see daily case numbers peaking at 314 a day by early December, including 16 ICU admissions a week.
Ardern and director-general of health Ashley Bloomfield presented the modelling on Monday, when Ardern revealed Cabinet's in-principle decision to move Auckland into step 2 of alert level 3 from next Wednesday.
But the model assumes the current level 3 restrictions in Auckland, and moving to step 2 will allow more ways for the virus to spread.
"I worry that it's too risky," Jackson told the Herald.
"I'd much rather we had the higher vaccination rate first and then we did the easing. But I also get the impatience of everybody [saying], 'look, I'm vaccinated, why can't I go and do my business?'"
Jackson said he would have waited another week and moved Auckland to step 2 in the middle of the month.
"That way there's only about two weeks until the [traffic light system] comes in, so you haven't got time to do too much damage." Read the full interview here.
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* 7.05am: Chris Hipkins
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Northern NZ into lockdown
Residents in the Far North went back into the strict lockdown at 11.59pm last night and are expected to remain there until at least Monday afternoon, when Cabinet next meets to review the settings.
It comes after an inauspicious start to the week for the region, during which health officials had announced only two new Northland cases since Monday - household contacts from Taipa. With only 14 known active cases, Prime Minister Jacinda Ardern even felt the wider Northland region was safe enough to visit yesterday.
But contract tracers have been stymied trying to find an epidemiological link for the Taipa cases, suggesting that community transmission could be more widespread than initially believed.
Far North District mayor John Carter said today that locals were expecting something like this to happen - after the area was plunged back into alert level 3 following new Covid positive cases in the area that have so far not been linked to the current outbreak.
"Quite honestly, the people are frightened," he told TVNZ's Breakfast show.
People were worried about the implications this might bring.
"That's why we're all working together. We'll stand up ... and get ahead of this thing."
Carter acknowledged the family involved and said they had done everything right and were co-operating with authorities.
The uncertainty about how the latest cases caught Covid-19 was a worry.
On the overall low vaccination rate in the region, Carter said it was important to remember that a lot of the population are young.
"A lot of our people are younger and they haven't been eligible for a jab until relatively recently."
But efforts are now being made to get vaccinations out to those groups.
Carter said he was confident those younger people would step up to take the vaccine - something local officials including community and iwi leaders had already started to see over the last two days.
He acknowledged the large Māori population in the district that remained unvaccinated, but said he was confident that that community would also step up to get the vaccine.
"We've just so far drawn a blank," director-general of health Dr Ashley Bloomfield told media in a hastily scheduled press conference alongside Covid-19 Response Minister Chris Hipkins.
"There was some debate about the need to increase the alert level, but the origin of these cases is unknown," Bloomfield added. "We are still trying to eliminate the virus outside of Auckland so our advice was a short period at level 3 to allow for more testing."
This time, however, the lockdown will encompass only the top half of the region - with a boundary line drawn from Hokianga Harbour to the Mangamuka Junction on SH1 to the Kaeo River Bridge on SH10 and East Bay. The boundary was determined in consultation with locals and local iwi, Bloomfield said.
While debating the merits of another lockdown, officials also considered the difficulty in conducting wastewater testing, since many residents use septic tank systems, and Northland's lower-than-average vaccination rate.
Had Northland been sitting at an 89 per cent vaccination rate, "we might be having a different conversation", Hipkins said, echoing Ardern's warning earlier in the day that the outbreak would not stay contained in Auckland forever.
With 79 per cent of eligible Northlanders having received a first dose of the vaccine, the region has the biggest gap in all of New Zealand before hitting the 90 per cent target, Hipkins pointed out.
Northland remains 17,120 doses short of reaching the 90 per cent target.
Far North Mayor John Carter called for everyone in the area to get vaccinated as soon as possible. While the renewed restrictions will be tough, he said he supported the Government's decision.
"The community are quite scared actually so the decision to put safety first, even though it will cause challenges for businesses in the interim, is the right way to go," he said.
The Far North's woes on Tuesday came after 126 new community cases of Covid-19 were announced by the Ministry of Health - including 18 new cases in Waikato and 107 new cases in Auckland.
Despite the relatively large uptick for Waikato, officials stuck with the plan for the region to slightly loosen some restrictions starting at 11.59pm last night. The region is now at step 2 of alert level 3. Retail shops, museums and libraries can now open with no limit on numbers, and outdoor gatherings can be held for up to 25 people.
But haircuts and most team sports remain banned in Waikato and working from home is still encouraged. Ardern has suggested Auckland will follow suit next week if there are no major surprises in the interim.
Unlike Northland, Waikato's 18 new cases yesterday - including six in Hamilton, five in Te Awamutu/Kihikihi, four in Ōtorohanga, two in Ngāruawahia and one in Kawhia - have all been epidemiologically linked.
Among Auckland's new cases were two more staff members at Edmonton Meadows care home in Henderson, bringing the number of active cases in that cluster to 12.
Two residents continued to receive care at North Shore Hospital, while the cause of the cluster remained unknown. A mobile testing unit was at the facility yesterday as the situation continues to be closely monitored.
Meanwhile yesterday, 17,665 vied online for summertime MIQ vouchers as officials released 3747 rooms for December, January and February. In total, 5483 people from 109 countries were able to get vouchers - with some of them sharing rooms.
Joint Head of MIQ Chris Bunny said another MIQ room release will take place on Tuesday.
"We understand that many people are wanting to return to New Zealand and are committed to continually improving our processes to help people do so," he said.
"There are still several thousand rooms to be released through to the end of February – we are closely monitoring our capacity in light of the community outbreak and will release as many rooms as we can through regular lobby releases."
The Ministry of Health also on Tuesday addressed the issue of Covid-19 in New Zealand's jails.
While there are a "small number" of cases in Corrections facilities, the virus does not appear to be spreading from prisoner to prisoner, health officials said. Instead, they said, infected prisoners are thought to have picked up the virus before they were brought into custody.
Sixty-seven per cent of prisoners nationwide have received at least one jab and more than 500 people have been fully vaccinated while in prison.
The nationwide vaccination rate for those eligible to receive it stood at 76 per cent yesterday for both doses and 88 per cent for one dose.
