The Government appears to have been concerned that New Zealand's unique "Covid-free" status and good healthcare system would mean the country was unlikely to sit high on the vaccine priority list.
An official document from August, released today, said if the global allocation of vaccines was assessed on need, New Zealand would be given low priority.
The document said the traditional drug-purchasing process was also likely to result in a long wait before the country could get a vaccine.
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That would be compounded by significant uncertainty about which trials would be successful and intense competition for the supply.
Many "advanced economies" were already "rapidly" making advance purchase agreements at the time the document was developed.
The document advised that a multilateral approach to obtaining a vaccine offered the opportunity to access a range of leading vaccine candidates with a "relatively modest outlay".
"A multilateral approach (COVAX), supported by GAVI, currently offers the broadest approach to access a range of leading vaccine candidates with relatively modest outlay. It will also only go some of the way to provide for our needs ... Participation by New Zealand would allow us to access enough vaccine to immunise 20 percent of our population."
It recommended that New Zealand needed to commit "significant resource early on to help secure access to a vaccine".
Having a range of advance purchase agreements would mean potential access to a range of vaccine candidates, but that would not guarantee access to a vaccine, as "it is likely that the majority of the candidates considered will not be viable".
Those pre-payments would not be recoverable once paid.
Determining the cost of those advance agreements would be difficult, money should be allocated in order to begin, the document said.
It expected early delivery vaccines could cost between $75 and $150 per dose when later delivery could cost less than $15.
Advice given suggested establishing an experienced negotiating team to secure the "best possible commercial deals" on vaccines as well as a framework for guiding those negotiations, and setting up a contingency fund now rather than appropriating the money outright.
The recommended amount for the contingency was redacted but was in the millions.
In late August, the Government announced "significant extra funding" to secure access to Covid-19 vaccine candidates when they become available.
The funding, from the Covid-19 Response and Recovery Fund, would be in the order of hundreds of millions of dollars. The Government said it would not disclose details of the funding because of commercial sensitivity, which could prevent a potential deal.
It advised decisions on use of the fund be given to the ministers of finance, health, research, science and innovation.
Another key objective mentioned was supporting Pacific nations with accessing a vaccine.