Officials who allowed two women out of isolation, on compassionate grounds, broke a rule which had been in force for four days.
Both women tested positive for Covid-19 after the pair drove from Novotel in Auckland to Wellington on Saturday, to visit a dying parent.
Speaking in a Facebook Live the Prime Minister Jacinda Ardern said that she did not think the way the exemption had been handled was acceptable.
Director General of Health Ashley Bloomfield says people must now return a negative result before being allowed to leave quarantine.
That rule has been spelt out on his Ministry's website since the 9 June.
Exemptions have now been suspended until the Health Minister is confident the mistake won't happen again.
Nearly 200 people have been allowed to quit quarantine early on compassionate grounds but it is not clear how many were first tested for Covid-19.
Otago University infectious diseases expert Professor Michael Baker says the case is concerning.