Lack of awareness mostly to blame
Around a third of companies who employ children have breached regulations over the last three years.
Registers have been checked 163 times since 2015 and found guidelines were flouted on 44 occasions.
The Department of Education, Sport and Culture released the data following a Freedom of Information request.
Of those identified most were considered to be 'low level' offences, coming about due to a lack of awareness about regulations governing young people's working hours and breaks.
The department has issued formal warnings to three companies since 2015.