The Vatican has failed to acknowledge the huge scale of clerical sex abuse and has implemented policies that have led to "the continuation of the abuse and the impunity of the perpetrators", a UN panel said on Wednesday in a scathing rebuke of the Holy See's handling of the global scandal.

In grimly worded findings released by the UN Committee on the Rights of the Child, the watchdog urged the Holy See to "immediately remove all known and suspected child sexual abusers" from their posts in the church and hand over the cases to law enforcement authorities in the countries concerned.

It also asked the Vatican to ensure that an expert commission set up by Pope Francis last year will "investigate independently" all cases of child sex abuse and the way in which they are handled by the Catholic hierarchy. Records concerning past cases should be opened up so that they can be used to hold the abusers – and those who may have sought to protect them – accountable, the panel added.

The Holy See must establish "clear rules, mechanisms and procedures" for the mandatory reporting of all suspected cases of abuse to civil law enforcement authorities, it said.

The committee said it was "particularly concerned" that in dealing with allegations of child sex abuse, "the Holy See has consistently placed the preservation of the reputation of the church and the protection of the perpetrators above children's best interests, as observed by several national commissions of inquiry."

The Vatican responded testily to the findings, saying that though it would submit them "to a thorough study and examination", it regretted what it perceived to be interference in its affairs. The statement was thought to refer to the committee's remarks on contraception and abortion.

"The Holy See does … regret to see in some points of the concluding observations an attempt to interfere with Catholic church teaching on the dignity of human person and in the exercise of religious freedom," said a Vatican statement.

"The Holy See reiterates its commitment to defending and protecting the rights of the child, in line with the principles promoted by the convention on the rights of the child and according to the moral and religious values offered by Catholic doctrine."

But the report, the recommendations of which are entirely non-binding, was welcomed by those who have long found the Vatican's approach to the scandal wanting.

"This day has been a long time coming, but the international community is finally holding the Vatican accountable for its role in enabling and perpetuating sexual violence in the church," said Katherine Gallagher, a senior staff attorney at the Center for Constitutional Rights. "The whole world will be watching to ensure that the Vatican takes the concrete steps required by the UN to protect children and end these crimes. Impunity and cover-up, including at the highest levels of the church, will not be tolerated."

Barbara Blaine, president of the US-based Survivors Network of those Abused (Snap), described the report as a "scathing" indictment of the way the Vatican had handled the scandal.

"It's a wake-up call, not to Catholic officials (who have known about and concealed abuse for decades and still do) but for secular officials, especially those in law enforcement, who can and should investigate Catholic abuses and cover-ups and prosecute the church supervisors who are still protecting predators and endangering children," she said.

As part of its wide-ranging remit, the UN committee also expressed concern about how the Holy See's stance on contraception, abortion and homosexuality was affecting minors.

It also said the Vatican needed to launch a full investigation into Ireland's Magdalene Laundries scandal in which thousands of women and girls were abused and enslaved. The report said those who abused and exploited those incarcerated in the laundries run by Irish nuns should be prosecuted if they are still alive.

It urged that "full compensation be paid to the victims and their families" who were caught up in the Magdalene system in Ireland.

While welcoming statements made by the Holy See delegation expressing a commitment to upholding the rights of children, the committee made clear its "deepest concern" about abuse committed by clergy operating "under the authority of the Holy See".

Tens of thousands of children had been abused by clerics worldwide, it said.

"The committee is gravely concerned that the Holy See has not acknowledged the extent of the crimes committed, has not taken the necessary measures to address cases of child sexual abuse and to protect children, and has adopted policies and practices which have led to the continuation of the abuse by and the impunity of the perpetrators," it wrote.

The report came two weeks after the committee grilled a Vatican delegation over the church's response to abuse allegations.

In particular, the committee slammed the practice of moving priests found to have abused children from parish to parish or to other countries "in an attempt to cover up such crimes". Last month a Vatican delegation in Geneva for questioning by the panel accepted criticisms of this practice and said it no longer went on.

But the committee nonetheless noted: "The practice of offenders' mobility, which has allowed many priests to remain in contact with children and to continue to abuse them, still places children in many countries at high risk of sexual abuse, as dozens of child sexual offenders are reported to be still in contact with children."

The UN panel also criticised the Holy See for refusing to hand over data concerning all cases of abuse brought to its attention during the period in question, and their outcomes. It said that confidential disciplinary proceedings had "allowed the vast majority of abusers and almost all those who concealed child sexual abuse to escape judicial proceedings in states where abuses were committed".

It also said the reporting of suspected crimes had been strongly hampered by a "code of silence" among the clergy which had seen those who dared to break it "ostracised, demoted and fired", and cited one well-known instance from 2001 in which a bishop was in effect congratulated for having kept to it.

Keith Porteous Wood, executive director of the National Secular Society in Britain, said Francis was now under pressure to prove his determination to take action.

"Pope Francis has already missed opportunities to assert his authority to reverse the church's damaging policies over clerical abuse and unless he responds positively and quickly to the demands of the committee, he risks history judging his whole papacy a failure," he said in a statement.

"Lawyers confirm that evidence abounds of the church at all levels continuing, even following the resignation of Pope Benedict, to do everything in its power to shield abusing Catholic clerics from justice and maintain secrecy, and do the least possible for victims," he said.

The Vatican was expected to issue a statement on the findings later on Wednesday.