Former minister Dermot Ahern has said the Vatican's most senior Cardinal sought an agreement under which Ireland would indemnify the Catholic Church against legal action for compensation by clerical child sex abuse.

Speaking to RTÉ News, Mr Ahern, who was Foreign Affairs minister at the time, said he was taken aback by Cardinal Angelo Sodano’s approach in 2004.

At the time, the Irish Catholic Church was a full decade into its child sex abuse scandal and, following the exposure of cover-ups into clerical abuse in Dublin, the Oireachtas had passed legislation to facilitate the establishment of a Commission of Investigation into the country’s largest and wealthiest dioceses.

In 2004, Mr Ahern was in Rome to mark the 75th anniversary of the establishment of diplomatic relations between the Holy See and the fledgling Irish Free State.

It was there he met Secretary of State Cardinal Sodano.

Mr Ahern said: "I got the impression he had just come from the United States, that there had been a major settlement costing millions which, he said, was over and above their moral responsibility.

"He asked for an understanding from the Irish government in relation to what might happen with future claims in Ireland against the Catholic Church there which, he said, would have severe financial implications for the Church in Ireland.

"As the conversation went on, it was quite clear he was referring to some sort of an indemnity, or part indemnity, from the Irish taxpayer in relation to anything that might come down the tracks. [He said this was] particularly in the context of the educational connection that priests have with our educational system," Mr Ahern said.

Two years earlier, Michael Woods, who was soon to be Mr Ahern's cabinet colleague, had struck an indemnity deal to pay all legal damages that survivors might win from 18 religious congregations which had run industrial schools and reformatories. 

In exchange, the Church promised to contribute €127m towards redress for victims.

When asked if Cardinal Sodano mentioned that controversial scheme when he raised the possibility of a second one covering abuse by priests, Mr Ahern said that he was aware of everything.

"He was fully briefed," Mr Ahern said.

"He knew what he was talking about in relation to Ireland. I cut off the conversation fairly quickly, to be honest."

The Vatican has not responded to requests for comment on Mr Ahern's recollections.