The Ministry of Health has confirmed there has been another instance where people were given the wrong dose of the Pfizer vaccine.
It follows the revelation that there were five people out of 732 who may have been injected with harmless saline solution instead of a Covid-19 shot at the Highbrook Vaccination Centre on 12 July.
Saline is used to dilute the vaccine once it has thawed.
After the incident was reported by RNZ, the Ministry of Health said it would contact all those who potentially got just saline, within 24 hours.
The Covid-19 vaccination programme's national director Jo Gibbs said there was also an incident at the Wigram vaccination clinic in Christchurch where vaccine stock did not match the number of doses administered.
"During the full-day clinic, six vaccinations were administered with a very low dose of vaccine."
The incident occurred as a result of a vaccinator picking up a tray of six syringes that had not had the correct vaccine drawn into them, she said.
"As a result of the investigation into this event, we know the affected cohort in this case is only six people because records show it occurred between 1.20pm and 1.40pm that day."
Gibbs said all six people have been contacted by the DHB and a clinical plan was developed for each person.
Four people were receiving dose one and two people receiving dose two on 14 July.
They have since been given another dose of vaccine.
Woman 'disgusted' she wasn't told of possible vaccination mistake
A woman immunised at the Highbrook Vaccination Centre in Auckland is disgusted she had not been told she may have been given just saline instead of the Pfizer vaccine.
Fiona Tolich, who was vaccinated on the 12 July said she was "disgusted" she had not been told about the mistake by the ministry.
She believed the ministry had no intention of telling her.
"You can't tell me they've taken five weeks talking to experts when internationally they were able to make the right call on the same day that it happened."
Tolich's partner is an essential worker and she has an underlying health condition.
She has so far only had one Covid-19 injection.
She said she can understand a mistake being made, but not knowing about it until now is appalling.
"People have a right to know what is being put in their body and they have a right to honesty and to me this screams of a lack of honesty and integrity and a lack of ethics."
She wants an apology from the ministry and an explanation.
Meanwhile, Health and Disability Commissioner Morag McDowell said she will be contacting the ministry about the incident.
"Consumers have the right to be fully informed about what may have happened to them.
"I understand that the Ministry of Health is working to resolve this matter and I expect that this will include informing the people who could have been affected by the error."
She said she will writing to the ministry to understand the actions being taken and to remind them of her expectations regarding the right of consumers to open disclosure.