The INLA has described as "ludicrous" allegations that elements within the prison service in the North colluded in the murder of the LVF leader, Billy Wright, in the Maze prison two days after Christmas 1997.
In a statement, the organisation said: "Should the demise of Billy Wright in any way have served to help other groups and/or state authorities, we regard this as merely coincidental and not a matter for our concern."
The statement, made to the Irish News yesterday, comes in the wake of demands by Billy Wright's father, David, for an independent inquiry into his son's murder.
Mr Wright alleges his son could not have been killed in "what is reputedly the most secure prison But the INLA said it alone decided to make an attempt on Billy Wright's life after a series of sectarian murders beginning in July 1996 with the murder of a Lurgan taxi-driver, Mr Michael McGoldrick.
Mr Wright's father claims that a prison guard was ordered off a watchtower only moments before his son was murdered. But the INLA statement stressed that it was to its "dismay" that there was no guard on watch duty on the morning of the shooting, claiming he would have automatically closed the perimeter gates if he had seen the INLA men on the roof of their barracks.
As a result, it claims, the van carrying Wright was almost able to drive out the gates, nearly foiling the assassination attempt.
An additional allegation that the INLA could not have cut a man-sized hole in a toughened security fence without being discovered by the prison authorities is also rejected by the organisation. Prison officials would not have had access to the INLA exercise yards except for general block searches which were unlikely to occur over Christmas, it said in its statement.
Mr David Wright has accused the British and Irish prime ministers of ignoring him and of operating a policy of "selective justice" in relation to his son's murder. Speaking in his Portadown home, Mr Wright said he found it "hurtful but not surprising that both premiers made time to meet with members of the Garvaghy Road Residents Coalition and the Nelson family to discuss their concerns, yet could not afford my family the same courtesy.
"Dr Mowlam has had the full facts of my son's murder on her desk for 14 months. What has she done? Absolutely nothing. Am I any less entitled to justice than the family of Rosemary Nelson, whose murder was horrendous and achieved absolutely nothing? I think not," Mr Wright said.
The Wright family was also dismissive of the INLA statement which said the organisation murdered Billy Wright unaided.