The Irish Cabinet has formally agreed to provide assistance to the UK’s inquiry into the Omagh bombing.
The dissident republican bomb exploded in the Co Tyrone town on August 15 1998, killing 29 people, including a woman pregnant with twins.
The UK Government has outlined its terms of reference for the independent probe, which will be chaired by Lord Alan Turnbull.
It will examine alleged security failings that led a High Court judge to conclude the atrocity could plausibly have been prevented.
Irish deputy premier and foreign affairs minister Micheal Martin and justice minister Helen McEntee secured approval to provide assistance to the inquiry at a Cabinet meeting on Tuesday.
A Government spokesman said this “honours a commitment” given to Omagh families.
The spokesman added: “Ireland has accepted the invitation of the inquiry chairman Lord Alan Turnbull to be represented at a preliminary hearing on the 30th of July.
“This is a complex process that involves working with another jurisdiction but we do have recent precedent for doing this.
“For example, the Omagh civil case and we also produced legislative means to assist inquests in Northern Ireland with Operation Denton and the independent review of activities into the Glennane gang.
“Officials will now explore a memo of understanding for the State’s engagement with this upcoming inquiry.”
Mr Martin has said the Government intends to do “everything possible” to assist the inquiry.
Officials from the departments of foreign affairs and justice continue to work with the inquiry team on how best to structure Irish engagement with the inquiry.
The inquiry will examine the adequacy of the measures taken by UK state authorities, including the police, security forces and intelligence and security agencies, to disrupt dissident republicans who had been involved in attacks from December 1997 up to and including the Omagh bombing.
It will assess whether that approach changed following the Good Friday Agreement of April 1998.
It will also probe alleged intelligence-sharing failures between the UK and Irish authorities in the year and a half leading up to the bombing.
A number of families of Omagh victims have repeatedly called for an inquiry to also be carried out into the bombing in the Republic of Ireland.
However, Mr Martin has previously said he did not think it made sense to have two separate inquiries on both sides of the Irish border.