Mr David Wright, father of the murdered LVF leader, Billy Wright, has accused the Taoiseach, Mr Ahern, of showing "utter contempt and indifference" for the unanswered questions about his son's murder in the Maze prison in December 1997.
Mr Wright, who met Government officials in June, also said "reliable political sources" in Dublin had said senior Fianna Fail officials were "actively pressurising some of their TDs not to become involved with my campaign for a public inquiry to be held into my son's assassination.
"When I met the Dublin Government in June, I was told my concerns would be made known to Mr Ahern within hours and a formal response would be made to me. I am still waiting for Mr Ahern to respond," he said. "Mr Ahern's attitude displays his utter contempt and indifference for myself and my concerns."
Mr Wright said this indifference indicated that Fianna Fail's claim to seek justice and equality for all the people of Ireland was "hollow political rhetoric without any substance whatsoever".
He asked the Taoiseach "to explain why he has failed to contact me and what are his reasons for not endorsing the calls for a public inquiry into my son's murder, which is after all a human rights issue".
Mr Wright said Mr Ahern had supported calls for inquiries "into the murders of Rosemary Nelson and Pat Finucane. Is my family any less deserving of justice?
"I can only assume that Mr Ahern's silence on this issue is due to a bout of the same amnesia which so clearly affected his memory recently concerning matters under investigation by the numerous tribunals which have bedeviled his administration since he took office," Mr Wright said.