Garda chiefs have still not overhauled the force as demanded by the Morris Tribunal seven years ago, State investigators have warned.
The Garda Ombudsman, which was set up as a result of the long-running corruption inquiry, said shortcomings flagged up by the probe into rogue officers had yet to be fixed.
In the latest broadside between the force and its watchdog, the Ombudsman also claimed the Garda was suffering a huge shock to the system from being asked to account for itself.
Carmel Foley, one of the three Garda Ombudsman commissioners, said the force had to undergo a culture change.
"We are conscious that the Garda have been here since the foundation of the State, and that a culture change is needed," she said.
"There is no doubt that oversight by a body (the Ombudsman) which is seven years in operation is a huge shock to the system."
Ms Foley said until the Ombudsman was handed oversight powers in the wake of the Morris Tribunal, no other State body could carry out activities similar to the Garda.
Speaking before a parliamentary committee, Ms Foley said officers were routinely unwilling to take part in even informal attempts to resolve complaints made against them.
Instead they "come in with their lawyers and say 'no comment, no comment, no comment'," she said, adding that it was often for minor issues like discourtesy or bad manners.
Simon O'Brien, chairman of the Garda Ombudsman, also hit out at the Garda for delaying its investigations and questioning the motives of the watchdog when asking for records or information.