POPE Francis has vowed concrete action on clerical sex abuse after telling his bishops to "listen to the cry of the little ones who are seeking justice.

The pontiff was speaking at an historic four-day summit of senior church figures after a series of scandals - including in Scotland - rocked the faith.

Religious commentators said his remarks signalled a change in language from mere condemnation of abuse to specific action to prevent it.

Francis told the Catholic hierarchy that it was their responsibility to deal effectively with the crimes of priests who rape and abuse children weighed on the proceedings.

He told the 190 leaders of bishops conferences and religious orders to "transform this evil into a chance for understanding and purification".

He said: "The holy people of God are watching and expect not just simple and obvious condemnations, but efficient and concrete measures to be established," he warned.

READ MORE: Kevin McKenna calls for public inquiry in to Scottish Catholic abuse

More than 30 years after the scandal first erupted in Ireland and Australia, and 20 years after it hit the US, bishops and superiors in many parts of Europe, Latin America, Africa and Asia either deny that clergy sex abuse exists in their regions or downplay the problem.

Last year an independent investigation for the Catholic Church revealed a horrendous catalogue of sexual and physical abuse against children in case of various religious institutions.

Dr Ben Torsney, of the University of Glasgow, found almost 400 cases or reports of abuse in Scotland between 1943 and 2005 during a probe launched at the behest of the Scottish Bishops.

Recorded allegations reached a peak in 1953 with 124 reports, and then began to fall with no more than five a year between 1990 and 2005, according to the study.

Many victims are therefore now pensioners.

The majority of the allegations concerned sexual abuse, which was mentioned 108 times. In total, 55 of the 59 allegations against priests involved sexual matters, while 265 were of physical abuse, one was of verbal abuse, and five were said to be emotional abuse.

Francis, the first Latin American pope, called the summit after botching a sex abuse cover-up case in Chile last year.

He has vowed to chart a new course and is taking the rest of the church leadership with him.

The summit is meant as a tutorial for church leaders to learn the importance of preventing sex abuse in their churches, tending to victims and investigating the crimes when they occur.

Abuse survivors have turned out in droves to demand accountability and transparency from church leaders, saying the time for cover-ups is over.

Phil Saviano, who helped expose the US scandal two decades ago, demanded the Vatican release the names of abusers and their files.

"Do it to break the code of silence," he told the organising committee on the eve of the summit. "Do it out of respect for the victims of these men, and do it to help prevent these creeps from abusing any more children."

The clerical abuse scandal has rippled through the Catholic world.

Activists in Poland on Thursday have pulled down a statue of a priest after increasing allegations that he sexually abused minors.

They said they were protesting over the failure of the Polish Catholic Church to resolve the problem of clergy sex abuse.

Video footage showed three men attaching a rope around the statue of the late Monsignor Henryk Jankowski in the northern city of Gdansk and then pulling it down to the ground under the cover of darkness.

The activists then placed children's underwear in one of the statue's hands and a small white laced church vestment worn by altar boys on the statue's body to symbolise the suffering of children allegedly molested by the prelate.

Police said the three men were arrested and that an investigation has been opened into whether they committed the crime of "insulting a monument", which can carry the punishment of either a fine or imprisonment.

Monsignor Jankowski, who died in 2010, rose to prominence in the 1980s through his support for the pro-democracy Solidarity movement and its leader, Lech Walesa, in their struggle against Poland's communist regime.

World leaders including US president George HW Bush and prime minister Margaret Thatcher visited his St Brygida Church in recognition of his anti-communist activity.

But in recent months, allegations have surfaced that Monsignor Jankowski abused minors, mostly boys.