Twenty-nine people, including a woman pregnant with twins, died in the Real IRA atrocity in August 1998.
There is currently no new evidence about the Omagh bomb atrocity which would warrant holding a public inquiry in Ireland, a minister has said.
However, Peter Burke, Minister for European Affairs and Defence, stressed that the Irish Government would cooperate fully with the UK Government in an attempt to ensure there are no unanswered questions left about the 1998 bombing.
Twenty-nine people, including a woman pregnant with twins, were killed when a massive car bomb exploded in the Co Tyrone town, the worst loss of life in a single incident in Northern Ireland’s troubled past.
It came just months after the historic Belfast/Good Friday Agreement.
No-one has ever been criminally convicted of the attack.
In 2021, a High Court judge recommended the UK Government carries out an investigation into the Omagh bombing, and urged the Irish Government to do likewise, after finding “plausible arguments” that there had been a “real prospect” of preventing the atrocity.
Earlier this year, Northern Ireland Secretary Chris Heaton-Harris announced that an independent statutory inquiry will be carried out.
Families of some victims of the bombing have urged the Irish Government to do the same.
Mr Burke, who attended a memorial service in the town at the weekend, told the BBC Good Morning Ulster programme: “We have had a number of previous investigations in this jurisdiction in relation to the events surrounding the Omagh bombing.
“Also we have had the Nally inquiry which was very detailed.
“The Nally inquiry found no significant new evidence which warranted the establishment of a public inquiry.
“That is our position at the moment. We have met with a number of survivors and victims, we are also awaiting the final publication of the terms of reference for the inquiry in the UK.
“We will be giving full cooperation with that inquiry. The Irish Government is very anxious to ensure that when that inquiry has concluded there are no unanswered questions.”
He added: “There have been a number of significant efforts and trials where we have tried to get convictions and hold to account those who perpetrated this heinous crime.
“The Irish Government wants to work hand in glove with the UK Government in relation to this issue and we will be cooperating fully with this inquiry.”
On Tuesday, a number of families who lost loved ones in the 1998 attack, gathered and laid flowers at the spot where the bomb exploded.
Speaking afterwards, Kevin Skelton, who lost his wife Philomena in the bombing, called on the Irish Government to “step up to the plate” over Omagh.
Speaking about the UK inquiry, he said: “Unless the southern government is involved, it’s a waste of time.
“If they do get involved, whether it bears fruit or not – I don’t know.”
He said the bomb was driven to Omagh from the Republic of Ireland.