An inquiry examining institutional sex abuse in Australia has heard 7% of the nation's Catholic priests allegedly abused children between 1950 and 2010.

In one religious order, over 40% of church figures were accused of abuse.

Over 4,440 people claim to have been victims between 1980 and 2015, the Royal Commission into Institutional Responses to Child Sex Abuse was told.

The commission, Australia's highest form of inquiry, is also investigating abuse at non-religious organisations.

It has previously heard harrowing testimony from scores of people who suffered abuse at the hands of clergy.

One victim said he was sexually abused by his Catholic Christian Brother teacher in his classroom, with other students ordered to look away.

In another case, the inquiry heard allegations that a priest threatened a girl with a knife and made children kneel between his legs.

'Children punished'

The full scale of the problem emerged on Monday, when the commission released the statistics it has gathered.

Gail Furness, the lead lawyer assisting the commission in Sydney, said more than 1,000 Catholic institutions across Australia were identified in claims of sexual abuse, with a total of 1,880 alleged perpetrators between 1980 and 2015.

The average age of the victims was 10.5 for girls and 11.5 for boys. On average, it took 33 years for each instance of abuse to be reported.

The victims' stories were "depressingly similar", Ms Furness said.

"Children were ignored or worse, punished. Allegations were not investigated. Priests and religious [figures] were moved. The parishes or communities to which they were moved knew nothing of their past."

Anthony and Chrissie Foster, the parents of two girls who were abused by their parish priest, said the Catholic Church had shown "no mercy, no remorse. Nothing."

"For so long this has been the way they acted to hide perpetrators, to move them on, with no regard for children whatsoever, that other children have become victims, and suffered this terrible fate," they told ABC news.