Pope Francis believes "about 2 per cent" of Catholic clergy are paedophiles, according to an Italian newspaper.

La Repubblica ran a three-page 'interview' with the Pope, in which he referred to the abuse of minors as like "a leprosy in our home" and branded the presence of paedophilia within the Church as "intolerable".

It is "the most terrible and unclean thing imaginable", the Pontiff continued, vowing to "confront it with the severity it demands".

He said his advisors estimated that 1 in 50 members of clergy were involved in child sex abuse, and – allegedly – noted that it includes "even bishops and cardinals".

"And others, even more numerous, know about it but keep quiet, they punish without saying the reason why."

However, a Vatican spokesperson has criticised La Repubblica for presenting the Pope's words as an interview without quoting Francis accurately.

Father Federico Lombardi released a statement highlighting that alleged quotes attributed to the Pope "come from the expert journalist Scalfari's own memory of what the Pope said and is not an exact transcription of a recording nor a review of such a transcript by the Pope himself".

Lombardi refutes the claim that Francis implicated "some cardinals" in the sex abuse scandal that has rocked the Church in recent years, despite the admission of Scottish Cardinal Keith O'Brien that his "sexual conduct has fallen below the standards expected of me as a priest, archbishop and cardinal".

O'Brien retired from public church life in February 2013 following allegations that he had engaged in "inappropriate sexual behaviour" with four men.

Lombardi did admit that "the overall theme of the article captures the spirit of the conversation", but also suggested that the newspaper may have attempted to "manipulate some naïve readers".

In the same conversation with La Repubblica's editor Eugenio Scalfari, the Pope is said to have promised to "find solutions" regarding to priestly celibacy, but Lombardi suggested these too were not the Pope's own words.

The Catholic Church has faced a wave of accusations relating to clerical sex abuse over the past few years. In September 2010, the details of around 300 cases of alleged sexual abuse by Belgian clergy were released, while a 2012 Australian police report detailed the suicides of 40 people who had been abused by Catholic priests.

Between 1984 and 2009, over 3,000 lawsuits were filed against Catholic clergy in the US, and the Church has reportedly paid out over $3 billion in settlements to victims.

In January of this year, a representative of the Church was forced to stand before the UN Committee of the Convention of the Rights of the Child to give account of the measures being taken by the Vatican to tackle the issue. At the hearing, the Vatican admitted it had defrocked almost 850 priests in the past 10 years as a result of abuse allegations.