The group also called for some of the older cardinals to absent themselves from the General Congregations, arguing that some have been accused of complicity in protecting priests accused of sexually abusing children.
"Their peers should push them to stay home, or they should do so voluntarily, the group feels, for the sake of the church and to avoid heaping more pain on wounded victims and betrayed Catholics," a statement on SNAP's website said.
One of Italy's anti-clerical abuse networks, L'Abuso, petitioned senior Vatican Cardinal Tarcisio Bertone on Monday not to allow the participation in the conclave of an Italian cardinal it alleges helped protect priests who molested minors in the past.
Cardinals must vote in person, via paper ballot. Once the process begins, the cardinals aren't allowed to talk with anyone outside of the conclave. They cannot leave until white smoke emerges from the Vatican chimney -- the signal that a new leader has been picked.
More than 5,000 journalists are now accredited for the papal conclave, Lombardi said Tuesday. They cover 24 languages, he said.