Opposition MPs and medical experts are backing the government's decision to make Pfizer New Zealand's main Covid-19 vaccine.
The government has secured enough doses for five million people to get the two Pfizer-BioNTech shots needed to be fully protected against Covid-19.
While National supports the decision, it said the government now needed to spell out exactly when New Zealanders could expect to receive their jabs.
Auckland University vaccinologist Helen Petousis-Harris is part of an independent panel giving the government scientific advice on Covid-19 vaccines.
She said she was "delighted" by the decision to invest in a vaccine shown to be about 95 percent effective.
Petousis-Harris did not have any concerns about the government seemingly putting all its eggs in one basket.
"The reason for having such a diverse portfolio of vaccines at the beginning was because we didn't have the results for any trials, we didn't know if any of these vaccines were going to work or how well. Clearly, this vaccine is an exceptionally effective vaccine," she said.
The government is still sticking with its other vaccine agreements and is looking to delay their delivery until next year, as well as to donate them to the Pacific and developing nations.
Covid-19 Response Minister Chris Hipkins said while the vaccine's ultra-cold storage requirements pose a logistical challenge, having just one vaccine would be much simpler.
"Rather than dealing with multiple different vaccines and having to sequence who gets which vaccine and how do we make sure that they're getting the same vaccine for their second dose as they would have got for their first dose and so on ... we will just focus on getting people vaccinated," he said.
Prime Minister Jacinda Ardern said the vaccines were expected to arrive throughout the second half of the year, and she has promised to give more detail on the planned rollout on Wednesday.
Although the cost of the vaccine is commercially sensitive, Ardern concedes that Pfizer was one of the more expensive jabs.
"No matter what vaccination you're talking about it all comes at a much lower price than the price of the loss of life, or what we've seen which is the ongoing hit that many businesses take if we have outbreaks.
"So in our minds, this is money very well spent", she said.
Petousis-Harris said New Zealand had already invested in the infrastructure needed to administer the Pfizer vaccine, "so we may as well use it".
And she said a simpler rollout could help address vaccine hesitancy.
"It keeps some of the messages consistent and messages we've already crafted and thought about.
"This vaccine, we've got an enormous amount of data on now and it's just consistently showing itself to be very, very good.
National's Covid-19 Response spokesperson Chris Bishop also backed the move.
"Overall it's good news. The Pfizer vaccine is incredibly effective. It's achieving really good results internationally, so it's good that New Zealand's going to get widespread access to it".
But he said it wasn't much comfort for New Zealanders who were still completely in the dark about the priority order for vaccines.
"We are entitled to expect transparency around when the vaccine will arrive here, and when New Zealanders can be lining up at their pharmacies and at their GP and at community vaccination clinics.
"That's the bare minimum that we need. Other countries, like the United Kingdom, for example, have actually published the contracts that they have with Pfizer. I think that would be a worthwhile thing for the government to do as well," he said.
Bishop said the prime minister would have no excuses if she did not front up with that level of detail when she spoke to the rollout plan on Wednesday.