An architect of the Catholic Church's response to clergy sex abuse will give evidence to the child abuse royal commission.

Retired Sydney Bishop Geoffrey Robinson will detail his discussions with senior Vatican officials and the Catholic Church's response to child sex abuse before the 1996 establishment of Towards Healing, its national internal scheme for handling abuse complaints.

Bishop Robinson, who retired as auxiliary bishop of Sydney in 2004, has long been outspoken about the need for the church to confront clergy sex abuse.

His evidence will include the operation of Encompass Australasia, a church rehabilitation program which operated from 1997 to 2008 to treat clergy with psycho-sexual disorders and those guilty of offending against children.

Bishop Robinson was the foundation chair of the program.

The royal commission will hold a public hearing in Sydney on August 24 to hear evidence from Bishop Robinson.