Published Saturday, 17 May 2014
Mr Kenny places a wreath for the victims. (© PA)
Thirty-three people were killed, including a pregnant woman, and almost 300 people were injured in the no-warning attacks on 17 May 1974.
Three bombs detonated in Dublin and one in Monaghan in the space of 90 minutes leading to what was the single worst day of atrocities in the Troubles.
The UVF has been blamed.
Taoiseach Enda Kenny joined families of those who died the atrocities as floral tributes were laid during a special memorial on Talbot Street in Dublin on Saturday morning.
It comes after members of the Justice for the Forgotten group announced on Wednesday their intention to sue the UK government over alleged collusion with loyalists.
A statement from Secretary of State Theresa Villiers on Saturday described the bombings of Dublin and Monaghan as "horrific atrocities" and offered her sympathies to the families.
She continued: "The passage of time does not lessen the pain and loss for those who lost loved ones to terrorism during the Troubles.
"There has been much investigation into the terrible events of 40 years ago.
"The previous government cooperated fully with the Barron and McEntee inquiries held in the Republic of Ireland, and went to great lengths to provide what information it could.
"Since May 2010 both my predecessor and I have discussed this issue several times with counterparts in the Irish Government and I continue to do so."
© UTV News