Former Attorney-General Sir Michael Cullen said he doesn't believe a Royal Commission of Inquiry is the best way to address historical claims of abuse in state care.
He also said New Zealand's legal system isn't set up to resolve claims like this.
"I have long held the belief that the adversarial system does not work to resolve these kinds of cases," he said in a written statement.
"Litigation ends up largely being a lottery. Those who can demonstrate a good case may end up winning large monetary compensation while others lose and miss out, or simply do not want to go through such a process."
"We now will have a Royal Commission. I hope it will satisfy those who suffered so much and are dissatisfied and angry… but the faith in Royal Commissions is as misplaced as faith in the Courts in that respect in many cases."
Sir Michael was responding to a Newshub Nation query about a compensation claim made against the Government by a former state ward in 2007, for abuse he suffered in state care.
The man lost his claim in the High Court on a technicality.
Sir Michael said it is undeniable that significant numbers of people were abused while in various forms of state care.
In 2008, he helped to establish the Confidential Listening and Assistance Service to hear from people who suffered ill-treatment in state care, in response to the rising number of claims.
Before the service closed in 2015 it heard from 1103 people. In its final report to Parliament it said: "As many boys as girls were sexually abused. About 57 percent of the men we saw had been sexually abused and 57 percent of the women."
The report also described the troubled lives many of the children went onto live: "Many of the children who had been abused in state care fell into anti-social and criminal behaviour and ended up in prison or psychiatric hospitals in later life. It is estimated that about 40 percent of prisoners grew up in state care."
The service, while able to listen to survivors and help arrange counselling for them, was not able to offer compensation, a limitation which increased calls from survivors for a Royal Commission of Inquiry.
In response, on 1 February 2018 Prime Minister Jacinda Ardern announced the creation of an abuse inquiry to be chaired by former Governor-General Sir Anand Satyanand.