A parent of a baby in Auckland City Hospital's Neonatal Intensive Care Unit has tested positive for Covid-19.
Movements in and out of the NICU have been restricted and all Auckland DHB staff in the unit are being tested, alongside babies and their families.
The NICU cares for newborn babies that are premature or are sick at birth and require extra medical care. The unit takes babies born pre-32 weeks.
Babies who are in the Auckland unit and those who have recently been discharged are being closely monitored. The DHB's initial investigations suggest the risk to babies in the unit is low.
Health officials are working to identify patients and staff who are considered to be contacts.
Plans are in place to manage staff levels until it is safe for everyone to return to work.
Some expecting mothers may be moved to other maternity units if their baby is likely to need NICU care.
Support is being provided to parents, patients and staff who may need it, including the Covid-19 positive parent and their family.
"The thoughts of the DHB, and the Ministry, are with this family as they manage the stress of a positive test result, as well as having a newborn baby in intensive care."
While in level 3, Auckland City Hospital visitors are restricted and are screened on arrival.
Two support people are allowed to attend throughout labour and birth until transfer to the postnatal ward.
A support person may also stay the night, by negotiation of the midwife in charge, and if a single room can be provided.
While in postnatal wards, a person can have two visitors who must visit one at a time between the hours of 7am to 8pm. However, all patients and visitors are asked to stay in their rooms and wear a mask when leaving the room.
It follows 33 new cases of Covid-19 announced on Sunday - it is unclear if the parent is one of these cases.
Two cases have been discovered outside of Auckland.
Hamilton, Raglan and several other Waikato towns moved to alert level 3 from 11.59pm on Sunday after the discovery of the two Delta cases, and the spread of the virus beyond Auckland's borders.
Prime Minister Jacinda Ardern announced the alert-level elevation at a hastily arranged 1pm press conference on Sunday following the discovery of the two Waikato cases - in Raglan and Hamilton East. Both people are known to each other but there is yet to be an established link to the Auckland outbreak.
As 33 new cases in total were announced, Ardern said level 3 would be imposed in Raglan, Te Kauwhata, Ngāruawāhia, Hamilton city and Huntly. The alert level would be reviewed in five days.
Hamilton will have spot checks around the boundary areas but it wouldn't be like Auckland's hard boundary for practical reasons, said Ardern. There were too many feeder roads into the Hamilton area, she said.
Ardern asked people to comply with the restrictions and work from home if they could.
The level 3 restrictions will apply for an initial five days while wide contact tracing, testing and wastewater testing takes place. Anyone with symptoms should get tested.