Nearly 800 newborn babies were taken from their mothers and put into government care in the past five years, with one Waikato baby taken within hours of its birth.
The 773 babies - all less than a month old - were taken due to "serious concerns" about their parents' ability to care for them.
Child, Youth and Family midlands regional director Sue Critchley described the removals as "absolutely the last resort".
"The last thing any social worker wants to do is take a newborn baby off their mother. So it has to be an absolute serious situation.
"When a baby is born it needs to be bonding with the parent and getting attached, so it's certainly one of the hardest calls we have to make."
The Midlands region (which includes Waikato and the Bay of Plenty) had the lowest number of babies taken (118) in the period, while the Southern region had the highest with 247 taken into care.
CYF would not reveal the age of the youngest child taken into care, but confirmed one Waikato baby was removed the day it was born.
Ms Critchley said most times before the baby was born a mother was aware the baby would be taken and family members were contacted to see if they could take it.
But there were cases where a baby was taken from a mother at hospital without warning after medical staff raised serious concerns, she said.
CYF deputy chief Bernadine Mackenzie said the court could grant a care and protection for them to take the baby as soon as it was ready to leave the hospital following the birth.
"These are very serious situations where it is assessed there are no other options for ensuring the infant's safety."
She said some babies continued to be breastfed under supervision, but the others were bottle-fed express milk.
CYF would not disclose specific reasons why the 773 babies were removed, but did say it could be due to a variety of reasons like serious family violence, chronic mental health concerns, addiction, previous abuse of older children or previous neglect.
Of those taken, 217 already had siblings in care.
Last year Chelsea Scott, the mother of a Ngaruawahia baby who died in unexplained circumstances, lost custody of her newborn baby within 48 hours of giving birth.
At that time no-one had been charged with the 2011 death of Serenity Jay Scott.
However, Miss Scott's partner - and the father of her new baby - Matthew Ellery was charged with murder less than a month after the new baby was born.
He pleaded not guilty to murder and will return to court next month.
- © Fairfax NZ News
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