More than 550,000 New Zealanders unlikely to accept a Covid-19 vaccination say that's because they'd rather wait and see if others get any side effects.

The Ministry of Health has released full results of polling into attitudes to the vaccine rollout, following an Official Information Act request from the Herald, and having earlier publicised only top-line findings.

Polling was done in September and December last year, and a report after the December polling shows:

• An estimated 555,100 adults who said they'd be unlikely to be vaccinated gave a main reason as, "I'd rather wait and see if others who have taken it suffer any side effects" - indicating this large group could be eventually convinced of vaccine safety.
• People who chose "I don't trust any vaccine" were more likely than average to live in the upper North Island (excluding Auckland) - 72 per cent live in the North Island, with 25 per cent in Auckland, 28 per cent in the upper North Island (excluding Auckland), 20 per cent in the lower North Island and 28 per cent in the South Island.
• 45 per cent of respondents were caregivers for at least one child, and, of that group, 40 per cent said "if an approved Covid-19 vaccine becomes available for younger children" they would have it given to a child or children for whom they were the caregiver. Another 24 per cent were unsure, with 33 per cent unlikely to do so.

Horizon Research did the polling in association with the University of Auckland's School of Population Health.

The ministry has previously only released a summary.

According to the full report on the December polling, 69 per cent of people would be prepared to accept a "well-tested and approved" Covid-19 vaccine, while 24 per cent were unlikely to. Eleven per cent (an estimated 391,900 adults) said they definitely wouldn't.

Those responses vary by ethnicity, and widely by age - 0 per cent of respondents aged 75 or over said they were "most unlikely" or definitely wouldn't accept a vaccine, compared to the 18 per cent "most unlikely" and 20 per cent definitely not of the 35-44 age group.

The polling asked if people agreed with offering the vaccine to some groups ahead of others, and 71 per cent were supportive, with 15 per cent neutral and 6 per cent unsure. Only 8 per cent disagreed with that approach.

There were four main places respondents said they'd go to for a vaccine - their doctor (75 per cent), a practice nurse (45 per cent), a medical specialist (40 per cent), or a "pop-up" clinic, such as in malls, shopping centres or parks (34 per cent).

The online survey in December had 1438 respondents, with the sample weighted to reflect the wider population. It has a maximum margin of error at a 95 per cent confidence level of ± 2.6 per cent.

Covid-19 vaccines are being widely used overseas and have shown very strong efficacy and safety results, and are also rigorously assessed by New Zealand authorities before sign-off for use here.

Vaccinations have so far been given mostly to frontline workers in managed isolation and quarantine facilities, and who work at or near the border, as well as some health workers.

The next phase will cover the people they live with, and then groups deemed at higher need or risk. The Government has said the general population will likely be offered vaccination in the second half of the year.

The Government has agreements to buy four different vaccines, and is aiming to vaccinate 90 per cent of the population. Director general of health Dr Ashley Bloomfield has said 70 per cent vaccination would be the minimum needed for herd immunity, depending on factors including vaccine efficacy.