Motorists without NCT certificates were wrongly prosecuted after having already paid fixed charge penalties, it has emerged.
Driving without a valid certificate became an offence attracting up to three penalty points in 2014.
Gardaí are to examine prosecutions over all fixed charge offences following the discovery.
The review has been launched to establish the extent of the problem and prevent further incorrect prosecutions, the force said.
District officers have been directed to withdraw prosecutions as cases with the same issue come before the courts. Any person affected by the mix-up will be notified in writing.
Gardaí said in a statement that it would "bring any matters to the attention of the courts as required".
A garda spokesperson was unable to clarify how many years of prosecutions will now be reviewed. The number of wrongful offences involved was also not immediately available.