Senior Catholic figures are "ready and willing" to assist with the royal commission into child sexual abuse in institutions, the church says.

The six royal commissioners have yet to determine a list of witnesses.

But the chief executive of the Catholic church's newly-formed Truth, Justice and Healing Council, Francis Sullivan, says the church is committed to "fully cooperate and engage" with the commission.

"We have no idea who the commissioners will ask to appear before them," he said.

"But one thing you can be assured of is the Catholic church leadership has made it clear they will fully cooperate so the people the commission wish to speak with will be there."

Mr Sullivan, whose council will be the conduit between the church and the inquiry, said the church wanted the "truth to come out".

"It's important for victims and people who have been damaged by the atrocities that their dignity is preserved and a process of justice can lead to healing," he said.

"But it's also important because a lot of mismanagement occurred in the past, but in the present there's improvement and we want to tell that story as well."

He said it was heartening to hear the government would be putting extra support services in place for people who may be re-traumatised by the experience.

But there also needed to be a long-term commitment to boost support.

Mr Sullivan said the commission would be worth it, whatever the final cost in dollar terms.

"The cost to people's lives is the biggest cost and royal commissions are not engaged lightly by governments," he said.

"But what it is saying is that this is an exceptionally important issue that the community wants to see addressed.

"People's lives have been lost, some families have lived with the damage of these scandals for most of their lives, and that cost is the greatest cost that needs to be addressed."