Almost half of all Māori tamariki taken into state care would go on to become adult inmates, a new report has revealed.

The report, tabled at the Abuse in Care Royal Commission of Inquiry today, also highlighted that one out of every three children and young people placed in residential care by the state went on to serve a prison sentence later in life.

The report outlined a significant disparity between those in residential care and the general population, for whom less than one in 10 ended up in prison.

Tabled during the examination of Oranga Tamariki at the Inquiry's State Institutional Response public hearing, the Care to Custody: Incarceration Rates Research Report is the first of its kind to analyse the interagency records of more than 30,000 children and young people between 1950 and 1999.

It showed Māori children and young people were more likely to end up in prison, with 42 per cent serving a custodial sentence as an adult.

The research document provides evidence of what the Royal Commission has heard time and time again through its work with survivors – a direct link between state care and criminal custody.

As with many historical records, there are limitations to the data that has been supplied by the agencies. Irrespective of these limitations, the research shows that people who spent time in state residential care were more likely to end up in prison.

The research was conducted by Synergia, an Australasian analytics, consulting and evaluation group.

The responses of state agencies to the abuse and neglect of children, young people and vulnerable adults are being examined by the Royal Commission of Inquiry in a public hearing that is running to August 26.

The Abuse in Care Royal Commission of Inquiry is investigating the abuse of children, young people and vulnerable adults within state and faith-based institutions in Aotearoa New Zealand between 1950 and 1999.

Last week, Police Commissioner Andrew Coster admitted many children had been let down by police responses to abuse in state care.

He told the commission children were physically, sexually, and psychologically abused over decades.

"It's clear that many have suffered greatly," Coster said in his opening statement. "It's also apparent that some have received inadequate service from the police. This has been difficult to hear."

For many of the children who ended up in state care, it was interactions with police that resulted in them being torn from their whānau.

The research, while confirming many of the horrific stories from survivors of state care, can also give some closure that their stories have been told and acknowledged.

- Joseph Los'e, NZ Herald