One in four New Zealand children have been involved with child protection services, according to new research.
The AUT study followed young people born in 1998 to 2015 and discovered nearly 24 percent of them were referred at least once.
Nearly 10 percent had been victim to substantiated abuse or neglect. Researchers also found three percent were put into foster care by 17 years old - mainly boys.
By 17 years of age, 3.2 percent of girls and 0.8 percent of boys had been sexual abused.
The report says the situation is worse than previously thought.
"Given the large number of children who touch the child protection system, our findings raise questions as to whether our child welfare systems are resourced and organised appropriately," the report authors wrote.
The study sampled more than 55,000 children.