O'Sullivan, 81, known as Brother Dominic while he taught at Marist Hamilton school in the 1970s, was sentenced on Tuesday for offences against two former students. The jail term will start in December, 2022 after he finishes a sentence for sexually abusing 23 former students at Marist Hamilton and Casino schools.

Newcastle District Court Judge Tim Gartelmann sentenced O'Sullivan after he entered guilty pleas to the fresh offences, consistent with earlier guilty pleas to all offences after he was first charged in 2013.

The sentencing occurred on the same day survivors of former Anglican youth worker James Brown, 70, were advised he had died in jail before his sentencing in May on a new round of crimes against children.

Brown died of a heart attack nearly nine years after he was jailed for 20 years for serious child sex offences against 20 children while an Anglican Church volunteer at Kurri Kurri from the 1970s to 1990s.

Brown was one of a group of perpetrators allowed to commit crimes in the Hunter for decades because of "systemic issues" and a "do nothing" approach by Bishop Alfred Holland.

The late bishop's failure to act on allegations about Brown represented a lost opportunity to stop Brown from molesting children, the Royal Commission into Institutional Responses to Child Sexual Abuse found.

O'Sullivan's sentencing and Brown's death came on the same day the second episode of the ABC series on the Catholic Church, Revelation, detailed the extent of child sex offending at Hunter Catholic schools, including Marist schools at Hamilton and Maitland and St Pius X College, Adamstown.

The series also expanded on the extent of offending against boys at the St John of God order's Kendall Grange facility at Morisset, featuring jailed child sex offender Bernard McGrath.

Hunter survivor advocate Bob O'Toole rejected Maitland-Newcastle Bishop Bill Wright's criticism of the series' "focus on the past", and said the most damaging sections were about the defence of discredited priests today, despite the royal commission.

"The culture of the Catholic Church is toxic and many changes are necessary for her survival - equal opportunity for women for one, acceptance of all, abolition of the boys' club mentality and freedom to speak without fear of reprisal," Mr O'Toole said.

He backed the Nash family of Hamilton, who demanded the bishop strip senior priest Bill Burston of the right to ministry for his comments on Revelation about Andrew Nash, who was 13 when he committed suicide at his home in 1974. Father Burston said he had "had enough of Andrew Nash", who the Marist order accepts was sexually abused by Marist Brother Romuald.