The National Party is pointing the finger at the government for dwindling Covid-19 vaccine supplies.
A further 50,000 vaccines arrived yesterday, bringing stocks to about 80,000.
However, Covid-19 Response Minister Chris Hipkins has warned that vaccine stocks will be at "almost zero" by next Tuesday, before the country receives another shipment.
As a result, the government is banking on another shipment of 150,000 doses arriving next Tuesday to avoid running dry.
"We have very carefully calibrated this, if the deliveries are late that might create a bit of a headache for us but we made that decision deliberately.
"We didn't want to have vaccine sitting in the freezer as a contingency, we'd rather get them out and into people, but it does mean we're cutting it very fine," Hipkins says.
However, National Party Covid-19 Response spokesperson Chris Bishop says the supply issues are of the government's own making.
"We are now bearing the brunt of decisions that we made last year and obviously at the start of this year.
"We made a decision to order quite late, we are one of the last countries in the world to order our vaccines and I think that has had a flow on effect in 2021."
The vast majority of district health boards have been vaccinating above vaccine targets, but are now being asked to scale it back.
Group 3, which includes amongst others people over 65, cancer patients and disabled people, are being told that they will be contacted to arrange a booking by the end of July.
Bishop says people in Canterbury from group 3 have told him they have been advised it could be as late as September before they receive their first dose of the vaccine, because there is not even enough for groups 1 and 2.
He says now should have been the time to ramp up the vaccine roll-out.
"We shouldn't be holding back because basically every week that goes by we almost run out and then another shipment arrives ... so we really do need to be putting the pressure on Pfizer to get that vaccine into New Zealand.
"I've floated publicly the idea of incentive payments as other countries have done to get Pfizer to deliver us some vaccines."
He feared a widely unvaccinated New Zealand public is a "sitting duck" for the Delta variant.
Covid-19 Response Minister Chris Hipkins told Morning Report Pfizer have been reliable about delivering on schedule.
"We are trying to get vaccines into New Zealand as fast as we can, bearing in mind they are balancing up our deliveries with other countries.
"If Pfizer deliver the million doses to New Zealand over the month of July which they have committed to, then we will by mid-July be delivering as fast as we possibly can based on what we're receiving.
"If we received more than that, it would give us a bit more comfort but it wouldn't necessarily speed up the rollout."
The AstraZeneca and Janssen vaccines are in the final stages of the Medsafe approval process.
Hipkins says quality assurance checks have held up the AstraZeneca application, with the supplier only recently revealing where it would manufacture the vaccine - in the United States at a new plant.
He says in total, there would be two million doses of the Janssen vaccine, with delivery expected some time between July and September, if it was approved.
"We wouldn't be able to use it straight away, so if we did need to use it as a contingency we would have some available.
"[It's] not as good as Pfizer, but it's certainly still a very good vaccine," he says, adding it was a single shot vaccine with a two-year shelf life.
In the meantime, Prime Minister Jacinda Ardern was optimistic that Pfizer would not delay the much needed shipment of vaccines next week.
"There is nothing to suggest that will be the case, consistently Pfizer have delivered when they said they will."
Much larger deliveries of vaccines are not promised to arrive until the third week of July.
The Ministry of Health is expected to give a vaccine update later today.