The government has purchased enough of the Pfizer/BioNTech Covid-19 vaccine for every New Zealander, Prime Minister Jacinda Ardern says.

Prime Minister Jacinda Ardern and Covid-19 Response Minister Chris Hipkins made the announcement at a post-Cabinet briefing about 4pm.

Ardern said the decision to make Pfizer New Zealand's primary vaccine provider was based on it being shown to be about 95 percent effective at preventing symptomatic infection.

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"Whilst the Pfizer vaccine does need to be kept at ultra-cold temperatures, this challenge is offset by only having to deal with one vaccine, rather than multiple vaccines with multiple protocols. It will simplify our vaccine roll out."

Ardern said the government had signed an advance purchase agreement for an additional 8.5 million doses on top of what it has already bought, bringing the total order to 10 million - enough for five million people to get the two shots needed to be fully vaccinated.

She said early evidence of the Pfizer vaccine's efficacy was 'extremely promising'.

"This purchase marks a significant milestone in New Zealand's fight against Covid-19. We can all take heart that we have now secured one of the strongest and more effective tools in the Covid-19 toolkit," Ardern said.

The additional vaccines are expected to arrive during the second half of the year.

Ardern said the purchase meant all New Zealanders would now have access to the same vaccine, which would simplify the vaccine rollout, so it would not slow the rollout of the vaccines at all.

Covid-19 Response Minister Chris Hipkins said the Ministry of Health was now working with Pfizer on the delivery schedule to ensure a "smooth rollout".

He said consideration was also being given to how best to use vaccine doses that would not end up being needed in New Zealand.

"We are working on options for donating surplus doses across our wider portfolio to the Pacific and developing countries worldwide.

"Options could include delaying delivery to New Zealand, in order to free up supply for other countries in the short-term, or donating spare vaccines to other countries," Hipkins said.

Hipkins said the Pfizer vaccine was the only one that had been approved by Medsafe and it was incredibly effective. He said having one vaccine to administer would make the process of getting people vaccinated more streamlined.

He said work was ongoing to ensure vaccinators had the right gear to administer Pfizer vaccine - syringes, freezers, etc. He said the government had enough for the first half of the campaign and was now in the market for the second half.

Using just one vaccine would simplify those equipment requirements, he said.

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Ardern said the government was making good progress with the vaccine rollout, with the vast majority of border staff and MIQ workers having received their first shots of vaccine.

She said household contacts of these workers had also been receiving the vaccine, roughly 50,000 people. She said the government expected to start the second tranche of vaccines - non-border frontline workers - later this month.

The Pfizer/BioNTech vaccine is more expensive than some of the other options.

"We've seen as a nation just how far we're willing to go to look after one another. And so I think it's fair to say no matter what vaccination you're talking about it all comes at a much lower price than the loss of life, or ... the ongoing hit that many businesses take if we have outbreaks.

"In our minds this is money very well spent, and spending it here on what is a highly effective vaccine where we won't have a situation of some New Zealanders getting one and some New Zealanders getting the other."

Ardern said the government was not putting all its eggs in one basket by securing 10m doses of the Pfizer vaccine, pointing to the other agreements it has with other vaccine manufacturers.

Hipkins says Medsafe had informed him the Janssen vaccine was farthest along in getting approved.

Ardern finished her speech on International Women's Day by acknowledging all the women who have played a part in the fight against Covid-19.

Reporting by Radio New Zealand

Republished by arrangement