Former Irish deputy premier John Wilson, appointed joint-chairman of the victims' commission created after the Good Friday Agreement, confirmed that he is urging a private inquiry under a former Supreme Court judge, with a published report.
His decision infuriated relatives of the dead and injured who suspect a cover-up by successive Irish governments.
Frank Massey whose daughter died in the Dublin explosions, said: "I am not going to have some faceless person telling me that I cannot attend the inquiry because it is private. Some people didn't want a report at all."
The May 1974 car bombs in Dublin and Monaghan, which killed 33 people and injured 300, generated repeated claims that the British military intelligence was involved in an attempt to secure tougher Dublin anti-terrorist legislation.
In 1993 the bombings were admitted by Loyalist UVF. Irish security sources maintained they lacked the expertise to produce such sophisticated devices, three of which blew up within 90 seconds in Dublin and a fourth in Monaghan 88 minutes later.
The RUC later confirmed it did not mount a murder inquiry and no one was ever charged in the Irish Republic.
Greg O'Neill, solicitor for the Dublin and Monaghan victims and relatives, said an inquiry held in private was not good enough.
"It is not going to address the sense of abandonment the bereaved and injured have felt over the years," he said.
Mr Wilson's report published yesterday included 40 recommendations on offering assistance to victims of the Troubles, from improved compensation to trauma teams similar to those formed to respond to the Omagh tragedy.
Mr Wilson's report follows recommendations from his Northern Ireland co-chairman Sir Kenneth Bloomfield.
It was completed two months ago but delayed by the search for missing bodies of IRA victims from the 1970s, in which the commissioners acted as intermediaries.
The Wilson report also urges a fresh inquiry into the killing of Seamus Ludlow, a 47-year-old bachelor who had spent an evening drinking in Dundalk and whose body was found north of the border town in 1976.Reuse content