UPDATE 3.15PM: Former Neerkol Orphanage resident Mary Adams has taken the stand to retell her harrowing experience when she was a resident in the 1950s and 1960s.
She has told of the severe physical and sexual abuse she endured from a Father John, who was relieving at the orphanage during a Sisters of Mercy retreat.
The commission also heard of the emotional evidence by a witness who said she was raped "well over 100 times" by a priest at St Joseph's Neerkol Orphanage Rockhampton in central Queensland.
EARLIER: EIGHTEEN witnesses, including Neerkol Orphanage survivors and Sisters of Mercy representatives, will share their stories at a public hearing as the Royal Commission into the institution gets underway.
Today marks a significant milestone for more than a dozen survivors, who lived at the orphanage between the 1940s and the mid-1970s.
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These survivors will tell their stories of the misconduct that took place at Neerkol Orphanage between 1940 and 1975.
The orphanage is plagued by a dark history, with stories of children being raped and beaten at the institution by a former chaplain, Sisters of Mercy nuns and a former groundsman.
Among those expecting to be called to give evidence on behalf of the Catholic Church was Truth, Justice and Healing Council chief executive Francis Sullivan.
The council was set up in December 2012 as a single representative body for the Catholic Church during the Royal Commission hearings into child sex and abuse across Australia.
Mr Sullivan said he was expecting the current head of the Sisters of Mercy institution and former Rockhampton bishop Brian Heenan to be among the 18 witnesses to be cross-examined during the hearing over the next two weeks.
"This latest hearing will see the leaders of both the Sisters of Mercy and the Rockhampton Diocese explain and be fully transparent about what happened at the time and also what has been put in place since to help former residents," Mr Sullivan said.
The hearing will be streamed live on the Royal Commission into Child Sex and Abuse website.
The institution was built in 1885, under the name the Meteor Park Orphanage, to accommodate children transferred from St Joseph's Orphanage in Bucasia.
It closed in 1978 when the children were transferred to Family Group Homes.