A number of premises were searched during the operation on Thursday.
Deputy Commissioner John Twomey said three members of the force are in custody and being held for questioning.
He said the force was committed to investigating any alleged “wrongdoing”.
“An Garda Síochána is fully committed to investigating any alleged wrongdoing or corruption involving Garda personnel, and will work with other relevant agencies in doing so,” he said.
“As this is a live and ongoing investigation, it is not appropriate to make any further comment at this time.”
The arrests were made in the course of an operation led by the Assistant Commissioner, Special Crime Operations (SCO), and involving personnel attached to the Garda National Bureau of Criminal Investigation (GNBCI) and the Garda National Drugs & Organised Crime Bureau (GNDOCB).
Gardaí said the superintendent had been arrested for suspected breach of the provisions of section 62 of the Garda Síochána Act, 2005.
The inspector was arrested for suspected breach of provisions of the Misuse of Drugs Act, 1977-84, and a member of garda rank had been arrested for suspected conspiracy to pervert the course of justice.
Section 62 of the Garda Síochána Act, 2005, relates to the disclosure of information obtained in the course of carrying out duties
With many thanks to: BBCNI for the original story