Reports said that members of the Parliament's Civil Liberties Committee ruled that blocking access to websites is acceptable only in exceptional circumstances as when a host server from a non-E.U. member country refuses to cooperate or takes too long to comply.
The unanimous 40-0 vote sides with Internet rights activists and Members of the European Parliament (MEPs) who were concerned about Internet freedom.
"The new generation of MEPs has shown it understands the Internet and has courageously rejected populist but ineffective and cosmetic measures in favor of measures aimed at real child protection," said Joe McNamee, of the European digital rights movement EDRi.
He added, "This is a huge and implausible success for an army of activists campaigning to protect the democratic, societal and economic value of the Internet," he added.
The move supports the idea that simply blocking a website does not guarantee that some offensive images may remain in cyberspace. And blocking could mistakenly remove a site that supports child protection as was the case where a Dutch website reportedly campaigning against child abuse was blocked twice by mistake.
Blocking will be permitted under unusual circumstances but the ruling stated it "Must be set by transparent procedures and provide adequate safeguards, in particular to ensure that the restriction is limited to what is necessary and proportionate, and that users are informed of the reason for the restriction."
In addition, content providers must be informed of their right to appeal.
But some supporters of child protection are concerned. "MEPs seem more concerned with the rights of child pornographers than they do with the rights of children who have been sexually abused," said John Carr of the Children's Charities Coalition on Internet Safety.
The European Commission also suggested that sites hosted outside of the E.U. could be blocked by law enforcement agencies or that it may assist ISPs by developing codes of conduct and guidelines for blocking access on a voluntary basis.
The decision also calls for tougher penalties for those who sexually abuse or exploit children that include a minimum penalty for 22 criminal offenses, including so-called online "grooming" of children, and allowing E.U. member states to impose tougher measures and sentencing.
Commenting on the ruling, Tim Henning, Vice President Technology and Forensic Research for the U.S.-based Association of Sites Advocating Child Protection (ASACP) said, "ASACP supports efforts that reduce the availability of child pornography on the Internet as well as tougher penalties for producers and consumers. I believe that the idea of blocking child pornography at the source has merit, however, those who end up making those decisions must be transparent and cautious to only block verified child pornography while providing a transparent and expedient method to dispute the decision in order to preserve Internet freedoms."