The son of murdered prison officer Brian Stack has rejected Gerry Adams' claims over a meeting he arranged with an IRA leader.

Austin Stack says the IRA leader, with whom he met in 2013, indicated that his father's killer was still alive at the time - and discussed the possibility of meeting with him.

He also disputes the Sinn Féin leader's contention that the IRA contact does not know the identity of the murderer.

The two men are disputing the details revealed to them by the IRA member at a meeting at a house in the border region which was arranged by Adams at the Stack family's request.

The IRA member told the meeting that while the organisation did accept responsibility for the shooting, it had not been authorised, and that the person responsible had therefore been "disciplined" internally.

Earlier Gerry Adams had appeared on RTE's Morning Ireland where he was repeatedly pressed on whether he would hand over the name of this IRA contact to the Gardaí.

Adams indicated that he would not, as the process of arranging the meeting with Stack had been agreed on the basis of confidentiality - and that no criminal proceedings would follow.

He also said he had not asked his IRA contact for the name of Stack's killer, and did not indicate that he planned to do so - suggesting, in fact, that the IRA contact did not know the killer's name either.

This afternoon Austin Stack confirmed to Today FM he had agreed to a confidential process - but accused Adams of being the first to break this confidentiality, by emailing the Garda Commissioner in February with the names of people who may have information.

On this basis, he said, he now felt free to assist the Garda investigation in seeking justice for his father's death.

He also contested Adams' claim that the killer may be head:

Political pressure is continuing on Adams to bring the name of his IRA contact to the Gardaí investigating the murder.

Stack, a prison warden in Portlaoise, was shot on his way out of a boxing match at the National Stadium on Dublin's South Circular Road in 1983.

The attack was not immediately fatal and Stack survived for almost 18 months before dying in late 1984.

Adams has said that any truth and reconciliation process must involve confidentiality, and that it is not feasible to pass over the details of his contact for this reason.

But that argument has been rejected by the finance minister Michael Noonan - who says if Stack was not murdered as part of a paramilitary campaign, the peace process cannot be invoked to shield his killers: