A new report says Marylands School and a related community centre for boys with learning disabilities in Christchurch says survivors described it as "hell on earth".
The Abuse in Care Royal Commission of Inquiry's interim report into the Catholic Order of St John of God, Stolen Lives, Marked Souls, was released on Wednesday.
It is part of the Royal Commission's wider investigation into abuse in state and faith-based institutions in Aotearoa between 1950 and 1999.
The report found widespread sexual and physical abuse at the Marylands School and Hebron Trust in Christchurch, both run by the Order.
It found more than one in five of the 537 boys who attended Marylands School reported abuse, which happened between 1955 and 1984.
But it said the real number could be much higher due to barriers to reporting of abuse by disabled survivors.
At Hebron Trust, youths were abused by Brother Bernard McGrath who has been convicted of more than 100 offences in New Zealand and in Australia.
A total of 21 of 37 brothers from the Order who ministered at Marylands School and in the Christchurch community had allegations of some form of abuse against them.
The report found children's cries for help were ignored by the Church, the Order and the State for decades.
Inquiry chair Coral Shaw described the Marylands School as a place of "depravity, sexual, physical and spiritual violence".
"We are aware of no other circumstances or institution where the sexual abuse has been so extreme or has involved such a high proportion of perpetrators over the same extended period of time as that at Marylands School," she said.
She said many survivors grew up to suffer life-long injuries and illnesses caused by the abuse and neglect, many had thought about suicide and some had lost their lives this way.
"When children reported abuse and neglect, they were not believed. Not believed by social workers, police, the brothers or the Catholic Church," she said.
Shaw said survivors had suffered for years and been robbed of their potential because those who were meant to care for them shamefully enabled the abuse and neglect, ignored it or covered it up.
She said without accountability, there can be no confidence that such events will not be able to occur again.
The report found the state and the school failed to protect the boys due to a lack of oversight of the brothers running the school.
It said evidence showed the Crown also may have breached Te Tiriti and its human rights obligations.
The final report with recommendations is expected in March next year.
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