Four people were fined €100 each during police patrols being carried out in the past 24 hours to ensure that there are no groups of four people.
The measure is one of a series being undertaken to control to spread of COVID-19.
Another 425 inspections were carried out on people in mandatory quarantine and no breaches were found.
A total of 945 inspections were also carried out on food and drink establishments in the past 24 hours and no breaches were found.