Child sexual abuse caused profound and lasting damage to scores of children who went to Marist in the late 1970s, 1980s and early 1990s.

The royal commission found the Marist Brothers Catholic order failed to intervene and remove offending brothers John Chute, known as Brother Kostka, and Gregory Joseph Sutton.

One survivor, former student Nicholas Quaine, first called for a permanent memorial in 2012 to recognise the school's past, but was rebuffed by Marist.

Headmaster Richard Sidorko has now agreed to not only install the plaque, but hold a healing ceremony on Thursday that will include a public statement of apology, and a commitment that the school will do everything in its power to prevent such acts from happening again.

Survivors, including Mr Quaine, have welcomed the measures as a positive early step by the school and an important symbol of a changed approach.

"I see it as a sign that the school has finally found some determination in the battle against sexual abuse and that they are done with the days of hushing up until it goes away," Mr Quaine said.

"The real challenge will be maintaining a high level of vigilance so as to avoid all potential future abuse," he said.

"For the sake of the kids I hope they can meet that challenge."

The wording of the plaque is strong, and comes largely from Mr Quaine's own suggested words. It reads:

"In remembrance of the students who were victims of sexual abuse at this school. Marist College Canberra acknowledges your pain and apologises for our failure to listen, to intervene and to protect.

"Let it never happen again. We are committed to the healing process and to reconciling our past with our hope for the future."

Mr Quaine said such a plaque will help prevent future abuse by telling students such acts are wrong and not tolerated by the school. It would give them the courage and vocabulary to speak out, he said.

"As a victim of sexual abuse I felt I was alone," he said.

"If such a plaque had been in place when I was a student at Marist then perhaps it would have been the factor that tipped the balance in favour of speaking out rather than staying silent."

The plaque will be unveiled after Thursday's healing ceremony, which is already expected to attract more than 200 people. The ceremony will be led by Father Peter Day.

The provincial, or head of the Marist Brothers in Australia, will attend, and Mr Sidorko will speak, apologising for the abuse and acknowledging that children had been failed.

"I don't for one minute pretend or expect that it's going to solve everything, I don't expect that it's going to take everyone's hurt away," Mr Sidorko said.

"I want it to be a statement of intent on our part, that we're owning what we've done, and we're deeply sorry for what we've done, and it's our determination that it will never happen again," he said.

Former Marist student and abuse victim Damian De Marco said it was "fantastic" that words were being locked in stone, to serve as a reminder that such abuse must not be allowed to occur again.

Mr De Marco said the words must be backed up by real action.

He wants the Marists to be part of a bottom-up push for cultural change within the Catholic Church. He said it was crucial that the church address the root causes of the abuse scandal, including changing policies on celibacy and women.

"Every child in the church is still at risk until the flawed modus operandi that facilitated and attracted the paedophiles is changed, fixed or removed," he said.

"[The plaque's words] will be there to haunt them if they don't actually become part of the solution."

Mr Sidorko said the school was significantly reformed, and now had an extremely strong child protection policy and a very sound pastoral record.

"We don't shy away from what happened, we don't hide it. We're not proud of it, but while it's also a point of shame for us, it's also a point of making sure we're better for it," Mr Sidorko said.