His son Austin Stack continues to deny Mr Adams' claims
Sinn Fein President Gerry Adams has reiterated that names he gave to Gardai in relation to the shooting of Brian Stack, were provided to him by Mr Stack's son.
Mr Adams said he spoke to Republicans - believed to be involved in the the murder of Portlaoise prison officer in the 1980s - at the request of Austin Stack in 2013.
However, Austin Stack denies that he met with Mr Adams.
Fianna Fail leader Micheal Martin, and Taoiseach Enda Kenny have called on the Sinn Fein leader to "come clean" about the issue.
But Mr Adams is insisting that he did meet with Austin Stack.
"Why would I suggest for one second that Austin Stack gave me names if he didn't give me names?" he told reporters. "C'mon."
He also said Míchael Martin's attack on him was a political one.
Brian Stack, who was the chief prison officer at Portlaoise, was shot in the neck by the IRA in Dublin in 1983. He died from brain injuries 18 months later.
Describing the murder as an "utterly unjustifiable act of pointless violence", Tanaiste and Justice Minister Frances Fitzgerald last night became the latest senior political figure in the Republic to ramp up the pressure on Sinn Fein.
"As Justice Minister it would not be appropriate for me to comment on the details of Garda investigations, but it is fair to say that serious issues have been raised in the public domain by Deputy Adams recently which require answers," she added.