He said he was “very worried” at recent incidents, including one last month where personal details on potential jury members were found in an apartment belonging to a close associate of gangland boss Brian Rattigan, who was convicted of murder last year.
Speaking at the annual conference of the Association of Garda Superintendents (AGS), Mr Ahern said officials from the Department of Justice were working with the Courts Service to limit who could access jury lists.
But he said defendants and their lawyers had a legal right to this information.
“I don’t think it’s an issue of restricting as such: every defendant – whether they are professionally represented or indeed representing themselves – would be entitled to have access to lists. It’s not something I think you can determine in legislation, it’s more administrative.”
Under the Juries Act 1976, defence lawyers, prosecutors, Gardaí and court officers are allowed to possess jury lists.
Mr Ahern said: “I think there needs to be tighter controls as to how these [jury lists] are made available and to ensure they don’t get into the wrong hands and indeed some of the information that’s available, maybe there doesn’t need to be as much information available about jurors as perhaps there is at the moment.”
He said efforts to address the problem “would have to be in conjunction with the Courts Service and the Department of Justice”.
Mr Ahern said he instructed his officials to examine the issue as part of an examination of juries, including their composition.
On AGS calls for more serious crimes to be tried in the Special Criminal Court, Mr Ahern said this was a matter for the DPP.
On the North, Mr Ahern said he was meeting Northern Ireland’s new Minister for Justice David Ford tomorrow in Belfast to discuss the growing threat from dissident republicans.
He said given that the police chiefs on both sides of the border met constantly, both he and his northern counterpart should do the same.
Mr Ahern reiterated that he believed the threat posed by dissident republicans matched the threat posed by paramilitaries during the Troubles.
Meanwhile, it emerged that nine superintendents were promoted to chief superintendent. They are Peter Kirwan, Jim Sheridan, Eugene Corcoran, Padraig Kennedy, Dave Dowling, Pat O’Sullivan, Tom Hayes, Ann Marie McMahon and Tom Curley.