Many primary schools are still turning to unqualified teachers to provide cover, despite directives requiring priority for places be given to those registered with the Teaching Council.
According to Department of Education figures obtained by the Irish Examiner through Freedom of Information, up to 1,500 individuals without adequate qualifications have worked in Ireland's classrooms since September.
Minister for Education Ruairi Quinn issued instructions in May urging schools to give a higher priority to those with qualifications when looking for temporary staff, while the Irish National Teachers' Organisation (INTO) directed its 30,000 members not to work with unqualified educators.
The publication noted some of these figures may be accounted for by those who have qualified, but whose registration was delayed, as a full breakdown was not available.
A spokesman for the Department of Education said: "We will be monitoring the situation, doing random checks and following up with individual schools where there appears to be an issue."
Last week, INTO urged newly qualified teachers to use substitute work to build their experience, rather than using the government's JobBridge internship scheme.