The slow development of three key IT systems is a major reason New Zealand's vaccination rate is the second-lowest in the OECD, National's Covid-19 spokesperson Chris Bishop says.
The National Party has published a leaked document which it says shows New Zealand has fallen far short of its original targets for the Covid-19 vaccine rollout.
About 90,000 doses of the Pfizer vaccine have been administered - slightly behind the Health Ministry's official plan.
Bishop said that the document, which dates from January, revealed a plan to have 390,000 doses administered by now.
Replying to the criticism, Covid-19 Response Minister Chris Hipkins said that the document was out-of-date and did not take into account the government's change in strategy to focus solely on the Pfizer vaccine.
Bishop rejected that, saying it was an internal Health Ministry document that focused on the use of the Pfizer vaccine.
"What he says is just wrong."
He said the document covered the first two phases of the rollout for the group 1 and 2 workers and envisaged that by this week 390,000 people would have received their first dose, and New Zealand now had even more doses than what the document predicted in January.
"But they're just sitting in the fridges. I think a lot of people out there are wondering... 'why can't I get a vaccine' when the Pfizer doses are sitting in cold storage around the country."
He said a big stumbling block seemed to be the IT systems which needed to be operational. Four of them had to be ready but three were not: the national booking system; the recall system (for the second dose); and the inventory management system which tracks where supplies are around the country.
It was hard to believe the latter one was still being developed, Bishop said.
"We're meant to be vaccinating thousands of people per day very soon and yet the IT systems are not ready to go.
"They started building them way too late ... we started basically in September last year - most countries started earlier than that.
"Most countries actually ordered the vaccines earlier than we did.
"We're now facing the cumulative effects of poor decision-making last year and of course that has consequences in 2021."
The low number of cases in New Zealand was a valid argument against a rapid vaccine rollout, but the UK had vaccinated 60 percent of its population and the US had done 50 percent while New Zealand had the second-worst vaccination rate in the OECD, Bishop said.
He did not say if he meant full or partial vaccinations.
Most figures show that for the UK, the full vaccination rate - people who have received the full course of doses - is about 10 percent and the rate for full vaccinations in the US is about 20 percent.
The partial vaccination rate in the UK is about 60 percent and for the US, about 32 percent.
Bishop said New Zealand should not be complacent, otherwise it risked being overtaken as other countries took advantage of trade, travel and tourism opportunities.
"The worry is the options for New Zealand will quickly diminish and we will be left behind."
He said if the rollout was done as fast as possible, the country would have plenty of opportunities to make the most of contact with the rest of the world.
- This article has been updated to clarify vaccination rates in the UK and the US.