A former Wollongong Catholic primary school principal will give evidence at the Royal Commission into Institutional Responses to Child Sexual Abuse.
Jim Walsh said he would tell the commission about his friend, whistleblower Father Maurie Crocker, who exposed paedophile behaviour within the Catholic Church in 1993.
Mr Walsh said he helped and supported Fr Crocker as he took the allegations of the victims to the relevant hierarchy - but when the police, priests and Bishop William Murray failed to act on the complaints, Fr Crocker had no choice but to take the matter to the Illawarra Mercury.
He said Fr Crocker was then ostracised by some of the clergy for exposing and speaking out.
"He was doing God's work," Mr Walsh said. "But he wasn't treated kindly at the time by the Catholic Church. I want to go to the commission and stand up for Maurie and for what he did."
Fr Crocker was a professional boxer and soldier before being ordained a priest late in life at the age of 42. He suffered depression and ended his own life in 1998.
One Wollongong priest, Fr Peter Lewis Comensoli, was jailed for abusing boys after being exposed by Fr Crocker.
Edmund Rice College principal Brother Michael Evans, who was transferred from Wollongong to oversee a building project on the North Coast, committed suicide the night before detectives were to interview him.
Mr Walsh said he later encouraged Fr Crocker to give evidence at the Wood Royal Commission - which he did.
Mr Walsh, who finished writing a book on Fr Crocker's life six months ago, has sent a copy of his work to the commission.
The ABC said on Monday that Mr Walsh was to give testimony about two priests from the Illawarra who had never been investigated for child sex abuse allegations.
But yesterday Mr Walsh retracted that statement telling the Mercury that though there were rumours in the 90s concerning the two priests because they had been sent overseas by the church, he had no proof that they had molested children, nor he said had he spoken to any alleged victims.
"There was talk at the time that that's how the church dealt with it by moving priests to some outward place," Mr Walsh said. "But I can't prove that it happened."
Mr Walsh was the school principal at St Therese Catholic School at West Wollongong until the end of 1993, when his contract wasn't renewed. He then worked for another year at the Catholic Diocesan Office.
"I don't know why my contract wasn't renewed but I would say my involvement in supporting Fr Crocker had something to do with it, but of course I can't prove that either," Mr Walsh said.
In a statement, Bishop Peter Ingham said allegations made by Mr Walsh that the Diocese of Wollongong failed to follow up sexual abuse crimes committed by two of its clergy were concerning.
"I fully encourage Mr Walsh to take these matters to the Royal Commission into Institutional Responses to Child Sexual Abuse as the commission is best placed to investigate them," Bishop Ingham said. "The Diocese has sought to co-operate fully with the commission and will continue to do so."