Three gardaí - including a superintendent and an inspector - have been arrested on suspicion of corruption.
Several premises in the southern part of the country were also searched this morning as part of the operation, which is linked to an investigation into a Limerick criminal gang.
The operation was led by the Assistant Commissioner for Special Crime Operations, and involved Garda divisions that deal with criminal investigations and organised crime.
One of those arrested is a superintendent, who is being questioned over a suspected breach of a law dealing with the sharing of information.
A Garda inspector has also been arrested for a suspected breach of the Misuse of Drugs Act.
Finally, a rank and file member is being held for suspected conspiracy to pervert the course of justice.
All three are currently in custody, and will be questioned on suspicion of committing one or more criminal offences.
Deputy Commissioner John Twomey said: "An Garda Síochána is fully committed to investigating any alleged wrong-doing or corruption involving Garda personnel, and will work with other relevant agencies in doing so.
"As this is a live and ongoing investigation, it is not appropriate to make any further comment at this time”.