Eighty-seven children in the Nelson-Tasman region have to be revaccinated after it was discovered the vaccines they previously received might be ineffective.
The vaccines were transported in a chilly-bin which became too cold, something which can affect their effectiveness.
The doses affected were the HPV vaccine against cervical cancer, and the booster for diptheria, tetanus and pertussis - both of which were administered within the last month.
Nelson-Marlborough medical officer of health Ed Kiddle said they have apologised to parents and recommended revaccination to ensure that the children are fully immunised.
He said they have taken steps to stop it happening again by introducing laptops and software that enable the temperature of the vaccines to be monitored more closely before vaccinations are done.