Child abuse survivors who reported the crime are being asked to tell how they were treated by police and the courts.

The Royal Commission into Institutional Responses to Child Sexual abuse has flagged that fundamental changes may need to be made to the criminal justice system when it comes to dealing with victims of child sexual abuse.

As part of its research the commission wants people who experienced the system, either as a complainant, a lawyer or a victims' support professional to share their observations.

Across 26 public hearings since 2013 evidence has been given of police in Queensland, NSW Western Australia and Victoria returning children to state and church-run homes even though they reported being sexually and physically abused at the institutions.

Evidence has also been presented on the failure of COPS - the police data base - when it came to keeping track of alleged pedophiles.

The failure in the case of former NSW Scouts leader Steve Larkin, who was jailed in 2012, meant he was able to continue offending for years despite allegations to police and NSW government departments.

In South Australia delays in a police investigation into allegations of child sexual abuse against Brian Perkins at St Ann's Special School in 1991 meant he was able to breach bail and leave South Australia around 1993.

The commission heard that in these and other cases there were problems with the way police communicated with parents of abused children and during trials, victims were sometimes re-traumatised.

In its interim report last year the commission announced it would be researching issues around prosecutions and trials, including how victims give evidence, jurisdictional differences in sentencing and how offenders with multiple charges against them are tried.

Directions given by judges in jury trials of child sex abuse cases will also be examined by the commission.

On Friday the commission published an issues paper, Experiences of Police and Prosecution Responses. It has invited anyone with personal or professional first hand knowledge to make a submission by June 15.

The submission can be made online to: criminaljustice@royalcommission.gov.au.