Cardinal Sean Brady is coming under pressure to resign
Cardinal Sean Brady understood oaths which swore alleged victims of a serial abuser to silence were not permanent, the Catholic Church has said.
Complaints of abuse by two teenagers against Fr Brendan Smyth were probed by the Irish primate in 1975.
A church statement said the Cardinal understood the oaths would no longer be binding after the taking of witness evidence was complete.
Pope Benedict XVI's letter on clerical abuse in Ireland is released later.
The complaints of abuse were investigated by Cardinal Brady in his previous capacity as secretary to the Bishop of Kilmore.
Smyth was jailed in the 1990s for a catalogue of sexual offences against children across a number of decades.
The statement was released by the Catholic Communications Office on Friday to correct a version of the oath published by a newspaper.
It said in the oaths, the two teenagers undertook to talk to no-one about their interviews except those who were taking the evidence.
They also pledged they had told the truth, the whole truth and nothing but the truth.
The statement reiterated that the intention of the oaths was to avoid potential collusion in the gathering of evidence and to ensure the process was robust enough to withstand challenge by Fr Smyth.
Earlier on Friday, a leading Catholic bishop in Ireland said he believed more cases of clerical sex abuse will emerge in Ireland.
Bishop Donal McKeown said the culture in the "1980s and early 1990s was very different from what it is now".
He said he was "sure" people had made "well-intentioned decisions" which later proved "disastrously wrong".
"I think whatever the truth is it has got to come out and the sooner it comes out the better," he said.
Bishop McKeown made his comments as the Northern Ireland Health minister, Michael McGimpsey, gave a paper to the Executive setting out options for dealing with historical child abuse in the jurisdiction.
Mr McGimpsey agreed to prepare the paper after the Assembly passed a motion expressing concern at the findings of the Ryan Commission into child abuse in the Irish Republic.