The Criminal Assets Bureau has raided properties in Limerick and Cork as part of a Europol investigation into international crime.
Gardai say the searches were carried out with armed Garda support.
The probe is into suspected criminal activity involving fraud, smuggling and theft of artefacts.
Dozens of raids have also taken place across the UK as part of the investigation.
Gardai say documents, cash and artifacts were seized during today's operation.
No arrests were made.