24 protected disclosures by staff or members of the gardaí were made to GSOC last year and over 400 criminal investigations were opened.
The garda watchdog's annual report shows almost 2,000 complaints detailing almost 3,000 allegations were made against officers, a slight drop on the previous year's figures.
Of 1,921 complaints received against gardaí last year - most related to abuse of authority, neglect of duty, discourtesy and allegations of assault, harassment or false imprisonment.
74 sanctions were imposed on individual members of the force while 415 criminal investigations were opened.
Gardaí received 15 referrals where the alleged conduct of an officer resulted in a fatality and 17 public interest investigations were opened by GSOC.
The DPP directed that four cases be prosecuted while another four were awaiting a decision at the end of last year.