A garda internal audit found that some officers were claiming overnight allowances for overnight trips that had not taken place.
Garda management had approved the practice instead of allowing those involved to claim for overtime, according to an internal audit that was carried out.
The practice came to light after an anonymous complaint saw garda college management carry out an initial review before asking internal auditors to do a full inquiry.
The audit of travel and subsistence payments at the Garda College also discovered other issues including the claiming of travel and subsistence expenses by members not stationed there without pre-approval.
Also discovered were claim forms that were not properly filled out while others had “vague descriptions” of the nature and location of duties carried out.
Internal auditors said they could provide only “limited” assurance on controls in place because of what they described as the “significance” of their findings.