In tears, church official Francis Sullivan told the hearing Monday, "these numbers are shocking. They are tragic and they are indefensible."
The commission's findings provide yet more evidence of a global epidemic of sex abuse and cover-up
within the church. Previous reports
have documented widespread abuse in the United States
, Ireland, Brazil, the Netherlands and Germany, among other countries.
The Vatican established a commission
to investigate claims of sex abuse in 2013, while in 2015 Pope Francis created a church tribunal
to judge bishops who failed to protect children from predatory priests.
Secrecy and scandal
As she delivered the findings Monday,
Senior Counsel Gail Furness said victims' accounts were "harrowing."
"The accounts were depressingly familiar," she said. "Children (who came forward) were ignored or worse, punished. Allegations were not investigated."
Priests who had been accused of abuse were moved to other communities that "knew nothing of their past," Furness said.
"Documents were not kept or they were destroyed. Secrecy prevailed as did cover-ups."
Scale of abuse
The commission has conducted 50 hearings since it was founded in 2013, and the history of sex abuse within the Australian Catholic Church has been well documented.
However, much of the evidence to date has been anecdotal and didn't quantify the extent of the problem.
The commission found, between January 1980 and February 2015, there were 4,444 victims of alleged sex abuse.
From three separate data surveys and witness testimonies, the commission found 7% of priests belonging to 75 Catholic Church authorities were alleged perpetrators.
The average age of victims at the time of abuse was 10.5 for girls and 11.6 for boys.
At least 1,880 alleged perpetrators were identified, according to the commission.
Of the alleged perpetrators, 32% were religious brothers, 30% were priests, 29% were lay people and 5% were religious sisters.
Within religious orders, the frequency was higher. Over 40% of St John of God Brothers were accused of abuse. The Order set up schools for boys with learning difficulties in the Australian states of New South Wales and Victoria, as well as New Zealand.
In a CNN interview Sullivan -- who heads the church's Truth, Justice and Healing Council -- said abuse had taken place on such a scale because priests "who have always been held in such high regard were never questioned. They were never in any way accountable."
He added: "Not only that -- people in positions of privilege covered it up. They were more interested in protecting the image of the Catholic Church than they were in protecting children and believing victims."
Sullivan told CNN that until those "at the very top" recognize that the problem "is how the church operates and its culture ... then they'll never get it."
Asked what will happen now in terms of securing justice for the victims, he replied: "The first thing in Australia is that the Catholic Church can no longer investigate itself. It can no longer attempt to resolve issues and complaints and claims. There needs to be an independent system away from the church.
"The second thing, which we've already started, is there's a new company that will audit the performance of bishops and religious leaders in how they do safeguard children. We'd have to put ourselves in the position, almost the church on its knees, so that it allows the victims to teach the church, not the other way round. A humble disposition for a change."
Over the next three weeks, the hearing will hear testimony from six archbishops. In a letter to parishioners around the country last week, President of the Australian Catholic Bishops Conference Archbishop Denis Hart warned that the hearing "may be a difficult and even distressing time."
"Deeply mindful of the hurt and pain caused by abuse, I once again offer my apology on behalf of the Catholic Church," he wrote, according to the ABC