The Pope's vow that no effort must be spared to prevent child sexual abuse and end its cover-up by the Catholic Church is "too little too late", an Australian victims' support group says.
In an unprecedented letter to the world's 1.2 billion Catholics, Pope Francis said the atrocities must be condemned and "this culture of death" uprooted to prevent the crimes happening and being covered up.
Broken Rites president Chris MacIsaac said the autonomous arms of the church decided what action to take in individual cases, often falling very short of dealing up justice for victims.
Ms MacIsaac said the church was still slow to accept responsibility in abuse cases and the Vatican should admit what it knew about the worldwide scandal.
"The Vatican must have known a lot about what was happening and their non-action was palpable," she told AAP on Tuesday.

The Pope has written a letter to Catholics, saying no effort can be spared to prevent child abuse. Source: AAP
Pope Francis said he was conscious of work in various parts of the world to ensure children were protected, but did not outline what the Vatican planned to do.
"We showed no care for the little ones; we abandoned them," he wrote.
Australian Catholic Bishops Conference president Archbishop Mark Coleridge said the bishops shared the Pope's determination to protect young people and vulnerable action, but called for action.
"These are important words from Pope Francis, but words are not enough," he said.
"Now is the time for action on many levels."
The Brisbane archbishop did not detail what action, ahead of next week's release of the ACBC and Catholic Religious Australia response to the child abuse royal commission's call for sweeping church reforms.
Victims' support group In Good Faith Foundation CEO Clare Leaney said it was encouraging to see the Pope addressing the whole of the Catholic Church, from cardinals to lay people, about what was a whole of church issue.
But she said existing survivors needed immediate care and support, recognising the life-long impacts of abuse.
"Survivors have been very strong in saying what they want now is affirmative actions to back up those words."
Ms MacIsaac said the church had been forced to accept child abuse was a crime, rather than treating it only as a sin.
"I think victims possibly feel in terms of recognition we've moved a long way, recognition of a huge blight on the church with the amount of sexual abuse that's taken place," she said.
The Pope's letter referred to last week's US grand jury report revealing church officials in Pennsylvania covered up the abuse of at least 1000 children by 300 priests over 70 years.
Australian church data released last year by the royal commission identified 1880 alleged perpetrators - priests, religious brothers and sisters and lay people - and 4445 victims over 60 years.