Major doubts about whether everyone will be vaccinated for Covid-19 by the end of the year have been raised by Auditor-General John Ryan.
He has released his review of the government's roll out plan, outlining several shortcomings in the government's plan.
"Problems were inevitable for a rollout of the scale and complexity of this one," Ryan said.
"I am not yet confident that all the pieces will fall into place quickly enough for the programme to ramp up to the level required over the second half of 2021. There is a real risk that it will take more time than currently anticipated to get there."
The lack of vaccinators posed a "significant risk" to getting the rollout done on time, and the Ministry of Health should get moving on the non-regulated workforce - non-medical workers who would be trained to immunise, Ryan said.
He said he had doubts that the supply of the vaccine would come quickly enough, saying the supply agreement with most companies was an indication only.
The ministry only had certainty of supply two months ahead and needed to work on a better contingency plan if it didd not get what it wanted, Ryan said.
Covid-19 Response Minister Chris Hipkins said he was still optimistic the country would be vaccinated before 2022, but he had never said it was a guarantee.
More work had been done on the number of vaccinators since the auditor-general's report.
Work was under way to change regulations to allow the non-regulated vaccinators to work, Hipkins said.
National Party Covid-19 Response spokesperson Chris Bishop said he shared the auditor-general's view that the country was at risk of not being vaccinated this year, but he hoped he was wrong.
The country risked having to stay closed as the rest of the world opened up, Bishop said.