DUBLIN — A prominent Irish survivor of priestly sexual abuse told a Vatican-sponsored conference Friday that the Holy See must put in place "robust structures" and strong sanctions to hold accountable bishops and Vatican officials who fail protect children from predator priests.

Marie Collins, a former member of Pope Francis' abuse advisory board, urged Catholic families attending the Dublin conference to ask why the pope scrapped such a structure — a proposed Vatican accountability tribunal — several years ago.

Collins was the headline speaker at a panel discussion on keeping children safe from pedophiles at the World Meeting of Families, a once-every-three-year Vatican-sponsored rally meant to encourage and energize Catholic families. Francis arrives Saturday in Dublin to close out the conference with a Mass on Sunday in Dublin's Phoenix Park.

While the sex abuse crisis was always going to cloud Francis' trip, given Ireland's devastating history of abuse and cover-up, new revelations in the U.S. of misconduct and cover-up by the U.S. hierarchy have ensured that Francis' trip will be dominated by the issue.

Cardinal Sean O'Malley, Francis' top abuse adviser, had been expected to head the Dublin safeguarding discussion Friday but stayed home due to what he called "serious pastoral needs" in Boston. O'Malley launched an investigation into his diocesan seminary, and removed its rector, after reports of misconduct went public.

It's the third seminary — including Philadelphia and Seton Hall, New Jersey — that are now under church investigation because of reports of sexual misconduct and possible abuse.

In a letter read out to the conference, O'Malley apologized for not being there in person but made clear he believed that protecting children was the single most important issue facing the Catholic Church today.

"All endeavors at evangelization and other great works will be dependent upon our ability to own our crimes and failings and to make the protection of children and vulnerable adults our No. 1 priority," his message read.

Collins, who resigned in frustration from O'Malley's panel last year, was more direct in demanding accountability for abusers and those in the church hierarchy who covered up for them, including at the Vatican.

"Anyone in the Vatican who would stand in the way of proper protection of children should be accountable as well," she said. "This accountability must have strong sanctions for the guilty: Dismissal from their post, removal of their titles and privileges and if necessary, removal from the clergy entirely."

Collins also said Catholics should ask why the church routinely opposes removing the statute of limitations for victims to prosecute and sue abusers, and yet claims to be on the side of victims. In his letter this week to all the worlds Catholics, Francis insisted that he was "on the side of victims."

"The actions of the church do not match the words, and they are in fact totally the opposite," Collins said to applause.