A man was arrested for dangerous driving after a cross-border operation targeting false mileage records.
The intelligence-led investigation focused on the manipulation of tachographs which record distances travelled and are commonly used on lorries.
Gardaí, Road Safety Authority (RSA) enforcement officers and the Driver and Vehicle Agency Northern Ireland identified targets who were intercepted at Dublin Port.
Gardaí arrested one man for using a magnet to create false records.
A statement said: "He was taken to Store Street Garda station and charged with dangerous driving and bailed to court in April."
Magnets interfere with and can compromise the braking and suspension system of a modern HGV.
Gardaí said another vehicle was detained as the certificate of road worthiness had expired in November 2017.
The operation was carried out on Thursday evening.
Following analysis by the RSA, a driver was found to be using a digicard (which stores information from tachographs) belonging to another person, and prosecution by the RSA is expected to follow.
An articulated lorry was seized by gardaí for having no insurance.