Bishop of Bathurst Diocese Michael McKenna's message to "dear friends in Christ" acknowledges paedophilia, past failure to deal with it appropriately and a commitment to "change our ways".

The letter, on the website of the Catholic Diocese of Bathurst yesterday, also appeared in newsletters read at masses in Dubbo at the weekend.

"In the Catholic Church, we already know that some of these offenders have been our own clergy and religious," Bishop McKenna said.

"They not only abused positions of trust, but also betrayed their sacred commitments. In addition to devastating emotional wounds, they have inflicted grave spiritual damage as well."

Bishop McKenna indicated more could have been done.

"It is already a matter of sorry record that, in the past, some church leaders dealt poorly with these incidents when they came to their attention," he said.

"We cannot undo those mistakes, but we can face up to them honestly and change our ways.

"In other words, as Christians, we are committed to repentance and reform.

"Contrary to the impression left by some media coverage, this work began in the Catholic Church long before the royal commission was called for. It will continue."

Ms Gillard's announcement on November 12 of a royal commission to examine institutional responses to child abuse had been welcomed by the Bathurst-based bishop.

Along with his fellow bishops, he promised to co-operate and expressed hope that "those who have suffered would be treated with respect and compassion and the commission would set itself at the service of truth and justice".

The subsequent message to the people of the diocese includes a warning.

"We cannot expect the royal commission to solve the whole problem of child abuse in our society," Bishop McKenna said.

"Most of it (child abuse) happens outside institutions and is driven by dark forces in human hearts that no court, only God, can defeat," he said.

"However, a well conducted royal commission could do a great service. It will succeed to the extent that it can separate truth from lies and pursue justice without creating new injustices. Those who will take on this onerous task deserve our co-operation and our prayers."

The message began with reference to victims.

"Our first concern should be that the inquiry is conducted in a way that is respectful and compassionate towards those who have suffered, both directly and indirectly, as a result of these evil acts," Bishop McKenna said.