A hearing is underway at the High Court in Auckland into a dispute over a seriously ill baby.
Te Whatu Ora is asking for the court to take over guardianship of the four-month-old baby to allow him to have the surgery that has been delayed because his parents do not want any blood used to be from a donor vaccinated against Covid-19.
The parents would still be in charge of the baby's non-medical care.
The Blood Service does not make a distinction between vaccinated and unvaccinated donors and says there is no extra risk posed.
After some name suppression submissions, Te Whatu Ora's lawyer Paul White opened its case, saying the baby had loving parents whose beliefs contrasted with the medical science.
The baby was sitting calmly with his mother in the public gallery with a tube in his nose.
White said it was not taking the case lightly but must act with the baby's best interests.
His parents had earlier consented to the baby having a transfusion and it was confusing why that has changed, White said.
Te Whatu Ora was also asking for the baby to remain at Starship Hospital.
About 150 anti-vaccination protesters were outside the court supporting the family.