Pope Francis has not yet shown the type of leadership needed to deal with child sexual abuse in the Catholic Church, a bishop has told a royal commission.

In a withering appraisal of how the church shrouds itself in secrecy when it comes to confronting its own faults, retired bishop Geoffrey Robinson said it had still not found the leadership it needed to tackle child sex abuse effectively.

The former auxiliary bishop of Sydney has for decades called for profound changes to deal with the church-wide blight.

On Monday he told the sex abuse royal commission those changes could mean examining the role of celibacy, putting women on the same footing as men and even re-visiting the misapplied notion of infallibility.

He said these suggestions would be viewed as heretical by most other bishops.

The church moved slowly, he said, and remarked that a 1922 papal instruction imposing a code of silence around child sex abuse crimes was so secret not even all bishops knew of it.

Bishop Robinson, a canon lawyer, said he thought popes had handled sex abuse poorly.

Pope John Paul II, who was pontiff for 27 years, could have sent out a message to the whole church but was silent, he said.

"So bishops were loyal to the silence."

Bishop Robinson who spoke several times about the need for strong leadership at different levels in the church said the problem of child abuse did not fit with Pope John Paul II's view of the church.

"A real leadership ... from the pope would have been marvellous, and from subsequent popes, now we still don't have that kind of leadership, not even from Francis", he said.

He said Francis was a new and different pope who had already raised big issues such as homosexuality and divorce and remarriage.

There are very powerful people opposing him "tooth and nail" so there was wisdom in him taking one step at a time, he said.

The bishop was also critical of Cardinal George Pell, who he said destroyed the unity of the church in Australia when he launched his own response to abuse victims before the official program.

Bishop Robinson said the establishment of the Melbourne Response by then Archbishop Pell in 1996, months before the Australian Catholic Bishops' Conference launched the nation-wide Towards Healing, was totally unexpected.

Bishop Robinson was the architect of Towards Healing, which is used by all dioceses except Melbourne.

He said Dr Pell's actions were taken without any reference to the bishops' conference and his truncated solution destroyed the unity of the church's response to abuse survivors.

He said Dr Pell alienated his priests when he became archbishop in Sydney.

The bishop also gave details of his own dealings with Vatican powerbrokers as he tried to get a church-wide response to the abuse of minors and told of frequent frustration when dealing with high-level Vatican committees.

Bishop Robinson encountered mindsets that did not consider pedophilia as the most serious of crimes when compared to crimes against the sacraments. He also met prelates who thought repentant child abusers should be reinstated as priests.