Gerry Adams is to be asked to reveal what he knows about the IRA's murder of Portlaoise prison officer Brian Stack, who was shot outside the National Stadium in Dublin 30 years ago and later died of his injuries.
Following a request from the family of Mr Stack, the Sinn Fein president has agreed to a meeting.
It is believed he was a senior IRA figure at the time, which the Louth TD denies.
Adams will be asked if he can furnish them with information about the murder.
It is suspected that father-of-three Mr Stack was killed because of his role in preventing a break-out of IRA prisoners from Portlaoise prison.
Mr Stack's eldest son, Austin, who is assistant governor at Dublin's Wheatfield Prison, has been campaigning for years to find out who was behind the murder of his father.
“This is definitely a move forward,” Mr Stack said.
“We have agreed to meet (and) we are still waiting on communication back as to a date,” he added.
Brian Stack was in charge of security in Portlaoise prison at the time of his death in 1984.
He was shot as he walked out of the National Stadium in Dublin after attending a boxing match and died from his injuries 18 months later.
Austin Stack believes that the IRA was responsible for the killing. “The modus, the opportunity and the ability lie with them,” he said.
“We still feel the answer lies within Sinn Fein.
“We are asking someone to take responsibility; we are not looking for revenge.”