A total of 50 people were prevented from entering Ireland from the North last week.
They were stopped without valid documentation, during traffic checks on the main Belfast to Dublin Road.
It is part of a ramping up of immigration checks under 'Operation Sonnet' - which is a joint policing initiative between the Gardaí and PSNI.
It is understood high-profile mobile patrols will now be conducted on a 'weekly basis' near the border, in addition to regular immigration checks carried out across all Garda divisions.
In a statement, a spokesperson for An Garda Síochána said: "Gardaí carries out immigration checks along the border on a regular basis to detect breaches of immigration legislation and detect abuses of the Common Travel Area (CTA).
"These checks are led and coordinated by the Garda National Immigration Bureau (GNIB). An Garda Síochána does not provide details or announce checks in advance or the specific details of operational matters.
"Checks can be spontaneous or pre-planned depending on the circumstances.
"Checkpoints are regularly conducted with roads policing units to facilitate the safe stoppage of vehicles.
"Checks are also conducted on the train line running through Co. Louth with checks conducted in Dundalk as the first entry point into this jurisdiction from Northern Ireland."
An Garda Síochána conducted 11 days of action in Q4 2023.
Up to May 20th, 2024 a further ten days of action took place, with four additional days of action taking place on the week commencing May 20th, 2024.
Up to that date, including Q4 2023, a total of 107 people were detected entering the State without the requisite visas or identity documents.
This week a further 50 people were detected entering the state without the requisite visas or identity documents and were ‘refused leave to land’.
They said during these operations, people entering Ireland illegally and were refused leave to land (RLTL) and returned to the UK by ferry from Dublin Port to Holyhead or returned to Belfast,depending on the individual circumstances.
