The bomb killed 29 people, including a woman pregnant with twins, and injured hundreds of others.
Tanaiste Micheal Martin has said Ireland will co-operate fully with a UK inquiry into the Omagh bombing, which he described as “one of the most brutal atrocities ever witnessed on this island”.
In a statement marking the 25th anniversary of the bombing, Mr Martin said: “We will never forget the 29 people who lost their lives, those who were injured, and the families whose suffering continues today.
“My thoughts are first and foremost with all those impacted by this attack, carried out with disregard for democracy, and for people.
“I have been honoured to meet with, and listen to, the families of the Omagh bomb victims over many years, most recently in June. Their search for the full truth of what happened has not been an easy or swift process.
“The Omagh bomb atrocity showed the appalling impact of violence on communities. The campaign of violence in Northern Ireland was never justified. We must keep working relentlessly on peace, dialogue and rebuilding trust.”
Earlier this year, Northern Ireland Secretary Chris Heaton-Harris announced that an independent statutory inquiry will be carried out into the atrocity.
Draft terms of reference have been shared with the Irish government but Mr Martin said it is his understanding the chair of the inquiry, Lord Turnbull, intends to seek the views of “those most affected” by the bombing before they are published.
Mr Martin, who is also Minister for Foreign Affairs and Defence, added: “Officials stand ready to engage with members of the UK’s inquiry team as soon as they are appointed.
“When we have further clarity on the nature of the UK inquiry, I will then consider, along with the Minister for Justice (Helen McEntee) and my Cabinet colleagues, the next steps in this jurisdiction.
“As has been done in relation to a number of historical inquiries, this State will co-operate fully.
“Justice for the victims and the families impacted by this atrocity will be at the heart of any action that the Government takes.”