There are fears that recordings of phonecalls in garda stations could impact trials, even where evidence within them was not used in court.
A number of lawyers say they believe if information in the tapes recorded at Garda stations was not disclosed in court it could re-open dozens of cases.
Taoiseach Enda Kenny has ordered the establishment of a Commission of Inquiry because of the potential impact on prosecutions and Tribunals.
Barrister Darren Lehane, who specialises in administrative law and tribunals, said the consequences could be far-reaching.
He said there are three categories of calls possibly affected: calls from people ringing garda stations complaining about issues, calls between clients and their solicitors and calls relevant to recent tribunals and inquiries.
"It does open up an appalling vista if there is information in the tapes that wasn't disclosed (in court, but) could have been pertinent, for example a conversation between two policemen talking about the manner in which they are investigating the case," he said.