The Taoiseach Mr Ahern today backed calls from relatives of Rosemary Nelson for an "independent judicial public inquiry" into the solicitor's killing.
The high-profile human rights lawyer died in a car bomb at Lurgan in March 1999, for which the Red Hand Defenders, a fringe loyalist group not on ceasefire, claimed responsibility.
After meeting members of her family and campaigners in Dublin, Mr Ahern said: "I recognise that Rosemary Nelson's case raises wider issues of concern to her family, to the public and to the international community.
"It is essential that the truth be established in a manner which will command the confidence of the whole community.
"For this reason, I am of the view that an independent, judicial public inquiry needs to be established into all of the circumstances surrounding her death."
Eunan Magee, Mrs Nelson's brother, said: "As a family it has been extremely frustrating.
"The Taoiseach is another person in a long list of people who have already called for a public inquiry into Rosemary's murder and I think having done so it has strengthened our case."
He said the next step would be for Mr Ahern to raise the matter with his British counterpart, Mr Tony Blair.
Mr Ahern also met Mrs Nelson's sister, Caitlin McVeigh, along with family solicitor Colm Owens, Paul Mageean of the Committee for the Administration of Justice and Jane Winter of British/Irish Rights Watch.
PA