His message will be watched closely by angry Catholics from Boston to Berlin to see if he acknowledges only the abuse itself -- or the decades of Vatican-approved cover-ups too.

Throughout the Catholic world, the church is only starting to come to terms with the scale of child abuse permitted in many of its parishes and schools throughout the 20th century.

The tide of scandal has surged from Canada and Australia in the 1980s, to Ireland in the 1990s, reaching the United States at the turn of the century and finally the pope's German homeland today.

Commentators and victims' rights activists agree that, to begin mending the church's battered image, the message to Ireland -- his first pastoral letter on child abuse in the church -- must break his silence on the pivotal role of the Catholic hierarchy in shielding pedophiles from prosecution. Including under the pope's own watch in Munich decades ago.

"Is it not time for Pope Benedict XVI himself to acknowledge his share of responsibility, instead of whining about a campaign against his person? No other person in the church has had to deal with so many cases of abuse crossing his desk," said the Rev. Hans Kung, a Swiss priest and dissident Catholic theologian.

"Honesty demands that Joseph Ratzinger himself, the man who for decades has been principally responsible for the worldwide cover-up, at last pronounce his own mea culpa," Rev. Kung said.

In Ireland, where the first major priest-pedophile scandal toppled the government in 1994, victims say they are tired of hearing church apologies that contain no acknowledgement of how bishops under Vatican direction let child molesters operate with impunity to preserve the church from scandal.

"What we probably will get -- I hope I'm wrong -- are a lot of expressions of regret and sorrow and apology about the horrors of child abuse in the past. I've heard that so often now," said Marie Collins, one of Ireland's most prominent campaigners for victims' rights. "I want to hear apologies for the actions of the church hierarchy."

Ms Collins, 63, was repeatedly raped by a Dublin priest, Paul McGennis, while in a children's hospital in 1960. Irish bishops knew at the time about McGennis' paedophilia -- including by confiscating his nude-photo collection of children -- but did not bar him from the priesthood until 1997 shortly before his conviction for abusing her and another girl.