Thirty-three people died and hundreds were injured when three bombs exploded in Dublin and one in Monaghan on 17 May 1974.

The event will take place in Dublin on Wednesday and will be followed by a mass in St Mary's Pro-Cathedral.

It follows a commemoration which was held on Sunday in Monaghan.

The ceremony took place at the site of the bomb in North Street when wreaths were laid by family members and also by families who lost relatives in the Dublin bombings.

An inter-denominational service was also held afterwards at St Macartan's Cathedral in the town.

The commemoration was organised by the group, Justice for the Forgotten, which represents the families of those affected.

The bombings, which were blamed on loyalist paramilitaries, caused the largest loss of life in a single day during the 30-year Northern Ireland conflict.

Speaking on Sunday, spokeswoman Margaret Urwin said it was important the events of that day were remembered.