Tánaiste Michael McDowell today rejected allegations that State agencies are trying to cover up the truth about the Dublin and Monaghan bombings.
The Minister for Justice told the Dáil he was "absolutely satisfied" his department had given "all the knowledge in its possession to successive Dáil committees and to Mr MacEntee", the sole member of the Commission of Investigation into the 1974 atrocities.
"It has held nothing back," he insisted.
Mr McDowell also said there was "every reason to believe that there was involvement at some level, of the security forces in Northern Ireland with some of the people involved in the attacks.
"That is a serious and grave matter, which I do not believe anybody now seriously discounts, bearing in mind what we know," he said.
The two-year Government-commissioned report by Mr MacEntee SC into the Dublin and Monaghan bombings in 1974 found no evidence that the winding down of the Garda investigation was linked to collusion.
A total of 33 people - including a pregnant woman - died and 300 were injured when four car bombs exploded in Dublin and Monaghan. It was the highest death toll on a single day during the Troubles.
The UVF was blamed for the attacks, but there have been persistent, but unproven, allegations that elements within the British military colluded in the atrocities.
Mr McDowell also dismissed a call from Sinn Féin's Dáil leader Caoimhghín Ó Caoláin for a full public inquiry into the circumstances surrounding the bombings.
"I believe the report deserves time and consideration, and it is something we have to come back to consider in this House in whatever we agree to do so," he said.
He then accused Sinn Féin of withholding information on who planted the bombs that killed 21 people in Birmingham in November 1974. Six men were wrongfully jailed for the attacks. Their convictions were overturned in 1991 after the original forensic evidence was found to be unsafe.
"When the deputy is calling for a public inquiry into that particular atrocity, we must remember that ... 21 people were killed in Birmingham and there was a massive miscarriage of justice.
"We have never had an inquiry and people much closer to him [Mr Ó Caoláin] know the truth of all of that."
The Garda today acknowledged Commissioner Noel Conroy had received Mr MacEntee's report.