On March 14, with only five confirmed cases of Covid-19 in New Zealand, an emergency cabinet meeting elected to impose unprecedented travel restrictions by requiring all travellers to self-isolate for 14 days.
Airlines and foreign governments - who respectively faced economic collapse and the potential stranded of tens of thousands of their citizens in New Zealand - were given only one hours' notice of the decision being announced publicly.
The March 14 briefing - followed later that day by Prime Minister Jacinda Ardern announcing the decision - is one of hundreds of documents released en masse yesterday afternoon outlining government policy-making during the Covid-19 emergency.
The documents show early decision-making on border controls and closures - prior to March 14 - was intended only to slow the spread of Covid-19 in order to buy the health system time to prepare for its expected unavoidable arrival.
This changed when the World Health Organisation declared the virus a global pandemic on March 12, with officials noting the number of cases globally had increased 13-fold in the three months prior.
"If our borders remain as open as they are now, there is a risk current people flows to New Zealand would precipitate more cases and fuel early stages of an epidemic here. Other countries have seen a few initial cases rapidly escalate into very high peaks of cases in a matter of days," the March 14 briefing said.
Airlines warned they were "deeply worried" about the consequences of such a move and expected the "entire market to Europe and the US would dry up".
Officials conceded that the requirements for all visitors to isolate would "have similar effects to a border closure in practice as it acts as a deterrent for visitors, who make up the vast majority of travellers."
The growth in the past few decades of international travel and the New Zealand tourism market also raise the prospect of tens of thousands of tourists being stranded - up to 40,000 European travellers were in-country at the time and expected to return home in the next four weeks.
The briefing noted the collapse of the aviation industry could, without support to maintain key routes, be catastrophic for the air freight market.
Officials noted airfreight accounted for 17 per cent of New Zealand's total value of traded goods, with more than 80 per cent of this usually carried in the bellies of passenger aircraft. Two-thirds of New Zealand medicines also arrive by air.
"These measures will have significant consequences for our ability to import essential goods if we cannot get airfreight into New Zealand."
In the weeks after that emergency cabinet meeting, the government announced a $600m aviation package largely aimed at maintaining key airfreight routes.
In the days following the border restrictions - which came into effect on March 16 - officials expressed concern that visitors were not following self-isolation rules.
"There have been increasing and credible reports from the hospitality, accommodation and conservation sectors that visitors are not complying with self-isolation requirements, and have no intention of doing so."
Briefings said police spot checks have "revealed that recent arrivals to New Zealand do not have a clear understanding of self-isolation requirements."
The travel restrictions were subsequtently tightened, removing thre ability of temporary visa holders to traveller here and expanding self-isolation requirements to even travellers from Covid-free pacific islands.
Pre-Covid, the country saw around 20,000 travellers arrive from overseas each day. By March 9 this was down to 5300. By March 16, numbers were down to 1360. It is understood in the past few weeks there have been days where this number has dropped to zero.