A number of items including fraudulent European ID documents, mobile phones and personal documents were seized during a multi-agency search operation in Meath on Wednesday.
Officers from the Garda National Immigration Bureau worked with officials from the Department of Social Protection and Work Relations Commission during the operation.
The first search was carried out at a commercial premises, where officers identified a "significant number of persons" working there as being illegally present in the State.
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Gardai said all of the people present were interviewed and a number of fraudulent documents were seized, along with personnel files and mobile phones.
Officers then carried out a subsequent follow-up search at a private residence where a number of items were seized including fraudulent European ID documents and electronic devices.
A garda spokesman said: "The operation involved in excess of 40 personnel, including interpreters and document examiners, and was led by the Garda National Immigration Bureau assisted by Garda National Drugs Organised Crime Bureau, Garda National Protective Services Bureau, Garda National Economic Crime Bureau, Garda National Cyber Crime Bureau, DMR Roads Policing, uniform Gardaí from the Ballymun District and officials from the Department of Social Protection and Work Relations Commission.
"Investigations are ongoing."
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