A Catholic bishop who more than a decade ago called for an end to the worldwide cover-up of child sex abuse by the church will take the stand at a royal commission hearing in Sydney.

Former Sydney Auxiliary Bishop Geoffrey Robinson, who helped write the church's sex abuse policy in Australia, will give evidence at a public hearing of the abuse royal commission on Monday.

The retired bishop will be questioned on the history and development of the Catholic Church's approach to abuse victims, and the 1996 establishment of Towards Healing, the internal church process for handling allegations.

The process has had mixed success.

Bishop Robinson, an expert on canon or church law, has for many years been outspoken on child sex abuse.

In May 2002, while still in office in Sydney, he called on Pope John Paul II to commission a worldwide study on the blight in the church.

In 2008, four years after he retired, he published a book - Confronting Power and Sex in the Catholic Church: Reclaiming the Spirit of Jesus - which called for profound changes in the way the church approaches sexual morality.

In May that year, just days before the bishop began a speaking tour in the US, the Australian Catholic Bishops Conference issued a statement criticising him for questioning church teachings.

In 2013, while the royal commission and Victorian and NSW inquiries were looking at abuse in the Catholic Church, Bishop Robinson published another book - For Christ Sake: End Sexual Abuse in the Catholic Church for Good - and launched a worldwide petition addressed to Pope Francis.

The petition called for an ecumenical council to tackle abuse and was also signed by bishops Bill Morris and Pat Power, both of whom had retired early after butting heads with the Vatican.

The three bishops said they were sickened by continuing stories of sexual abuse and were appalled by accounts of an unchristian response to those who had suffered.

Among the matters they wanted a council to consider were the teaching of the church on sexual morality; the effects of obligatory celibacy; the lack of a strong feminine influence in the church; and the constant placing of right beliefs before right actions.

In early 2015, Pope Francis set up a church child-protection commission, which includes clerics and lay people. The Pope wrote to the heads of national bishops' conferences demanding close and complete co-operation with the new body.

It's likely that at Monday's hearing Bishop Robinson will be asked his opinion on the Pope's actions.

The bishop will also be asked about Encompass Australasia, a church rehabilitation program he chaired for clergy with psychosexual disorders, which operated from 1997 to 2008.

In his evidence, Bishop Robinson is expected to detail his discussions with senior Vatican officials over the years.