A police report on deaths caused by family violence shows about half of child victims were killed by their mothers.
The report considered 101 deaths between 2004 and 2011, which were studied using the Family Death Review system.
Eighty two other family violence fatalities occurred during the same period, but only deaths reviewed using that system were included in the report.
It shows 33% of victims were children, 36% women and 31% men.
It also shows 81% of women were killed by their partners or ex-partners, compared to just 29% of men.
Mothers were responsible for 45% of the children's deaths, with 15% dying shortly after birth and their bodies disposed of.
National crime manager Superintendent Rod Drew told Radio New Zealand's Checkpoint programme while the number of mothers killing their children is alarming, the figures here are consistent with other countries.
"What it does is tell us that there are some intervention points, whether it's through social or cultural things which may or may not be to do with the concealing of pregnancy, or it might be to do with some mental health issues, so there are things that can be worked on by those involved in the family violence area."