The Ministry of Health initially didn't want the traffic light system to be used until at least 90 per cent of the population aged 5 and up, as well as among Māori and Pasifika, were fully vaccinated.
This advice was provided to the Government on October 10 and is contained in a number of official documents that were made public yesterday.
The Government instead opted for a 90 per cent target in each DHB region before the new system would be implemented, a benchmark it eventually scrapped.
The country has been in the traffic light system since December 3, and the Auckland boundary is set to be softened from December 15.
The documents also reveal that the Government took a more precautionary approach than it originally envisaged for the new system, including requiring the use of vaccine passes in hospitality venues and gyms rather than just high-risk events, and extending their use into the green setting as well as the orange and red settings.
Public health advice had recommended putting only Auckland and Northland into the red setting, but Cabinet also decided to include a number of other North Island districts, from Whanganui northeast to Gisborne, because they were holiday hotspots for Aucklanders.
Ministers also decided to keep the Auckland boundary in place instead of lifting it at the same time the country went into the new system, which was the public health recommendation.
Meanwhile, the independent advisory group chaired by epidemiologist Sir David Skegg told the Government the new system would widen existing health inequities, particularly for Māori and Pasifika.
That was because they were less vaccinated, more likely to live in crowded houses and had higher rates of comorbidities and more barriers to accessing healthcare.
Health staff 'tipping point'
A public health assessment on November 17 noted the pressure that testing labs were under, with only 49 per cent of tests being turned around within 24 hours.
Reducing testing for lower-risk essential workers coming and going from Auckland was recommended to ease the pressure on testing labs.
This is despite a case in Canterbury having travelled to Auckland to attend a tangi in the last week.
"The public health service is increasingly becoming stretched and is potentially reaching a tipping point where staff will be lost," the Minister of Health was told, as staff supported 5010 to isolate at home including 2238 cases, the Health Ministry document, dated November 18, said.
Work was under way to change the way case investigation and contact management was done to make it more sustainable, but "the easing of workload is yet to be realised".
Shifting Auckland to step 3 of level 3 - which never eventuated - was of "little value" before moving to the traffic light system.
The Government has since announced a plan to boost PCR testing capacity to 60,000 a day.
Meanwhile, Cabinet did not appear to consider whether travellers leaving Auckland should need to be both vaccinated and have a negative test.
A November 15 Cabinet paper stated that the options to consider were for travellers to be either vaccinated or tested, or to have no travel prerequisites at all - though a substantial section of the paper is redacted.
The Health Ministry supported no prerequisites because of high vaccination coverage around the country and confidence in the use of the red setting.
"Requiring a predeparture PCR test as well as vaccination would increase the protection, but the Ministry of Health officials advise that this would be unsustainable for more than a very limited time as demand for tests would overwhelm capacity."
The paper also notes that police and transport officials will be busy over the summer period.
The paper, from Prime Minister Jacinda Ardern and Covid-19 Response Minister Chris Hipkins, noted that easing restrictions on the Auckland boundary will see the virus being taken out from the city to different parts of the country.
"The degree of undetected infection is the key factor for the risk of interregional transmission (detected cases are expected to stay at home and not travel)," it said.
"Any loosening of the boundary with Auckland, coupled with high numbers of reported cases in Auckland, would mean that we must expect infected people to travel across New Zealand."
The most likely destinations for Aucklanders leaving the city included Northland, Waikato (particularly in the Thames Coromandel district) and Bay of Plenty.
"In communities with lower rates of vaccination, transmission can be expected to be quicker. This means that outbreaks would be larger at the point they are detected, and harder to contain once they are detected."
These risks would be mitigated by increasing vaccination coverage, especially among the vulnerable, and starting Auckland in red.