The National Party is calling on the Government to have a target in place for what percentage of the population should be vaccinated against Covid-19.
Some 27,000 people had their first vaccination so far, with 60 per cent of those in Auckland.
Covid-19 Response Minister Chris Hipkins said there had never been a fixed target for the number of vaccinations.
"Our target ultimately is to get as many people vaccinated as possible."
Hipkins reiterated the vaccine is not going to be compulsory.
"As we look of the later part of the year, particularly that fourth quarter, the biggest challenge for us there is going to be to get people to be vaccinated.
"We know towards the middle of the year as we ramp up and make it publicly available there will be a lot of demand, that demand will start to tail off and that is that last group who is going to be the challenging group."
He said officials were also awaiting information on whether under 16s should be vaccinated.
National's Covid-19 response spokesman Chris Bishop said he would like to see the Government introduce a target soon.
"We want to achieve herd immunity, we want as many New Zealanders vaccinated as possible and I think a target would help.
"It does seem out of line with what other countries are doing."
Bishop said having a target would also help hold the Government to account.
He added New Zealanders would also like to keep track of how the fight against Covid-19 is going.
"When we all pulled together during the big lockdown last year, that did create a real sense of taking it seriously as a country and quite a good feeling of national pride.
"I think we should try and engender the same feelings when it comes to the vaccination programme too."