Spanish campaigners have delivered a petition with more than half a million signatures to the national parliament in Madrid demanding an extension of the statute of limitations in child sex abuse cases.

The organizers of Thursday's event say many child abusers in church, state and sports institutions have gone unpunished because their alleged crimes were reported only many years later by their victims.

Miguel Hurtado, a spokesman for victims' group Stolen Childhood Association, says the 15-year statute of limitations for child sex abuse cases should begin to run only after an alleged victim reaches 50 years of age.

Currently, it begins after an alleged victim turns 18. The Spanish government has proposed that the statute of limitations should begin when an alleged victim turns 30.