The United Nations has demanded the Vatican "immediately remove" all clergy who are known or suspected child abusers and turn them over to authorities.

In an unprecedented report, the UN Committee on the Rights of the Child said Catholic Church officials had imposed a "code of silence" on clerics to prevent them reporting attacks to police, and moved abusers from parish to parish "in an attempt to cover up such crimes".

It said the Holy See must hand over its archives on the sexual abuse of tens of thousands of children so culprits, as well as "those who concealed their crimes", can be held accountable.

The Vatican responded quickly, saying the church was committed to "defending and protecting the rights of the child" and promising to give the UN report "thorough examination".

However, it also added the UN was interfering in Catholic moral teachings because the report also criticised its positions on homosexuality, contraception and abortion.

The watchdog's exceptionally blunt paper - the UN's broadest critique of the Catholic hierarchy - followed its public grilling of Vatican officials last month.

"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," the report said.

It urged the Vatican to "immediately remove all known and suspected child sexual abusers from assignment and refer the matter to the relevant law enforcement authorities for investigation and prosecution purposes".

At a press conference following the release of the report, the committee's Kirsten Sandberg said the Vatican had "systematically" placed the reputation of the church over the protection of children.

"They are in breach of the Convention [on the Rights of the Child] as up to now, because they haven't done all the things that they should have done," she told reporters.

Sorry, this video has expired UN accuses Catholic Church of protecting paedophile clergy ( Mary Gearin )

The president of US-based group Survivors Network of Those Abused by Priests, Barbara Blaine, says she is pleasantly surprised by the UN report.

"This is what we, as victims have been saying for decades," she said.

"The brave survivors in Australia who have spoken up, this acknowledges what they have been saying and I believe it also affirms the necessity for the royal commission that is taking place.

"We have been trying every which way we can to get church officials to step up and do the right thing and what we've learned over time is that the only time that they take even the barest of minimum of steps is when they are forced to from external sources."

The UN's call for full disclosure was backed by the head of the Catholic Church's Truth Justice and Healing Council in Australia, Francis Sullivan.

"The real challenge for the Vatican is not to get defensive, but to be open and demonstrate what they are going to do to give confidence back to not only the Catholic community, but the community generally," he said.

Vatican 'regrets ... attempt to interfere with teaching'

In a statement, the Vatican said: "The Holy See takes note of the concluding observations on its reports, which will be submitted to a thorough study and examination... according to international law and practice."

Global Catholic Church abuse cases Australia: Priests, brothers, charged over more than 100 offenses against children dating back to 1970s at St Stanislaus school, Bathurst. Royal Commission into Institutional Responses to Child Sexual Abuse, launched in April 2013. Expected to hear from 5,000 victims. Canada: Mount Cashel Orphanage, Newfoundland, closed in 1990 after it emerged staff abused 300 residents over several decades. In 2002, associations representing more than 10,000 self-declared victims joined forces to seek compensation. US: A 2004 criminal investigation found 4,400 priests sexually abused minors between 1950 and 2002; abuse affected about 11,000 children. Former archbishop of Boston Bernard Law forced to resign in 2002 for having protected paedophile priests; former archbishop of Los Angeles Roger Mahony agreed to pay $US660 million to 500 victims. Ireland: One priest admitted sexually abusing more than 100 children, another said he had abused minors regularly over 25 years. A total of 14,500 Irish children are reported to have been victims of abuse by clergy. Germany: In early 2010, hundreds of alleged cases of child sex abuse in church institutions emerged, notably at the Jesuit college Canisius in Berlin where about 20 cases were reported. In late 2012, a report said at least 66 church officials had been accused of sex abuse. The Netherlands: In late 2011, a report said "several tens of thousands of minors" had been abused within church institutions between 1945 and 2010, and around 800 suspects have been identified.

But the Vatican also reacted strongly to what it said was interference in church teachings after the UN called on the institution to amend its attitudes.

Archbishop Silvano Tomasi, the head of the Holy See's delegation to the United Nations in Geneva, defended its record on combating sexual abuse.

"It is very difficult I think to find other institutions or even other states that have done so much specifically for the protection of children," he said.

The report urged the Vatican to "review its position on abortion which places obvious risks on the life and health of pregnant girls" and called on it for greater flexibility in "identifying circumstances under which access to abortion services can be permitted".

It also called on the church to "make full use of its moral authority to condemn all forms of harassment, discrimination or violence against children based on their sexual orientation" in an effort to help "the decriminalisation of homosexuality" internationally.

The Vatican said it "regrets 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".

It added it "reiterates its commitment to defending and protecting the rights of the child... according to the moral and religious values offered by Catholic doctrine."

The UN said the Catholic Church had not yet taken measures to prevent a repeat of cases such as Ireland's Magdalene laundries scandal, where girls were arbitrarily placed in conditions of forced labour.

It called for an internal investigation of the laundries and similar institutions so that whose who were responsible could be prosecuted and that "full compensation be paid to the victims and their families".

It also said priests who had fathered children should be held accountable and made to provide for their upkeep.

A commission created by Pope Francis in December should investigate all cases of child sexual abuse "as well as the conduct of the Catholic hierarchy in dealing with them," the report said.

"We expect the Holy See (and the Pope) to follow up on these recommendations... to protect victims and give them compensation," Ms Sandberg said in Geneva.

At a public session last month, the UN committee pushed Vatican delegates to reveal the scope of the decades-long sexual abuse of minors by Roman Catholic priests that Pope Francis called "the shame of the church".

The Holy See's delegation, answering questions from an international rights panel for the first time since the scandals broke more than two decades ago, denied allegations of a Vatican cover-up and said it had set clear guidelines to protect children from predator priests.

ABC/wires