The committee also said it needs to set up its own complaints mechanism.
Rape and sex crimes can amount to torture or cruel treatment and the Vatican must prevent and punish such abuses, it said. It had already found that sexual abuse amounted to torture in some 50 countries, officials said.
Committee member Felice Gaer, said: "The Holy See says sexual abuse is not torture. Well, sexual abuse, including rape, can be torture, or cruel, inhuman and degrading treatment. We say whether it's cruel treatment or torture depends on the facts of the case."
It was the second time this year that a UN human rights body has criticised Roman Catholic officials' handling of the decades-long sexual abuse of minors by priests.
Victims accuse the Vatican of still protecting abusers and covering up sex crimes, failing to punish perpetrators, refer them to the authorities or provide adequate compensation.
The Vatican told the committee this month that the Church's accusers were "fossilised in the past" when public attitudes were different.
Earlier this month, former West Lothian priest Thomas Mullen was dismissed by the Vatican after decades of allegations of sexual abuse.
The Holy See said the committee had not found it in violation of the treaty and recognised its "important efforts to prevent sexual abuse". It said: "The Holy See condemns sex abuse as a serious crime and a grave violation of human dignity," adding that it would give "serious consideration" to the recommendations.