Legislation allowing greater admissibility of tendency and coincidence evidence was introduced into the NSW Parliament this week and follows from the findings of the Royal Commission into Institutional Responses to Child Sexual Abuse.

The Commission heard about many criminal proceedings in which evidence of an accused person previously offending against children was ruled inadmissible due to courts' concerns that it may unfairly prejudice the accused person.

In November last year, the Council of Attorneys-General meeting agreed to implement a "model bill", following a two-year development and consultation process led by a NSW working group.

ACT Attorney-General Gordon Ramsay said the government had agreed in principle to implement all recommendations of the Royal Commission.

"In certain circumstances this evidence is already admissible," a spokesperson for Mt Ramsay's office said.

"The reforms will improve outcomes for victims to ensure that evidence submitted is better recognised as having probative value."

NSW Attorney General Mark Speakman has been the first to act on the vexing legal issue and says that "it can't undo the horrors of the past".

"But we can make sure that our legal system offers a fairer and more effective response for victims and survivors," he said.

The reforms also make it easier for multiple sex abuse victims to give evidence against the same offender in the one trial setting, rather than having to do so repeatedly in separate proceedings, which can re-traumatise victims.

Re-traumatisation has emerged as a high risk in many child sex abuse cases with parents having to choose between exposing their child to further trauma to achieve justice, or allowing paedophiles to remain free in order to prevent the system causing further psychological harm to their child.

Child Abuse Royal Commissioner Robert Fitzgerald AM said consistent, nationwide reform on this issue was one of the most important recommendations of the Royal Commission.

"Over many years, Australia's criminal justice system has failed to provide adequate justice for survivors of child sexual abuse, in part because of the unnecessary exclusion of tendency and coincidence evidence in criminal proceedings," Commissioner Fitzgerald said.

"Following the Royal Commission's comprehensive inquiry, and in the context of alarmingly low conviction rates for child sexual assault offences, we were convinced of the need for change."

Data provided to the Council of Attorneys-General meeting revealed that between July 2012 and June 2015, conviction rates for child sexual offenders in NSW was 60 per cent, as opposed to 89 per cent for other offences.