In this file photo crosses and an image of Pope John Paul II hang inside a church, on the outskirts of Madrid. AP
Unlike in many other nations where the government or the Church itself has opened an investigation into such abuses, Spain has only recently made moves to follow suit with lawmakers in March backing the creation of an independent commission.
The independent panel is made up of 20 people, mostly experts, but does not include representatives of the Church.
Spain's ombudsman, Angel Gabilondo, who is in charge of the probe, on Tuesday "presided over the first constitutive meeting" of the commission, his office said in a statement.
The aim is to "prepare a report on sexual violence within the Catholic Church and the role of the public authorities", it said, indicating that the panel included 17 experts "with experience in victimology, in the care of victims and legal knowledge".
There is no deadline for completion of the report.
The initial idea was that members of the clergy would be on the committee but Spain's Catholic Church said it would not directly participate although it would "collaborate with the authorities, providing all available information about the cases under investigation".
It believes the commission should be looking into cases involving the abuse of minors within all of Spanish society and not just the Catholic Church.
Long accused by victims of stonewalling and denial, the Spanish Church in February tasked a private law firm with an "audit" into past and present sexual abuse by the clergy, teachers and others associated with the Church.
With no official statistics on child sex abuse within the Church, Spain's El Pais newspaper began investigating allegations in 2018.
It has so far counted nearly 1,600 victims.
In March, the Spanish Church said it had discovered more than 500 cases of child sex abuse through a complaints procedure launched in 2020.