Thousands of unqualified people are teaching in schools across the country.
New figures show more than 14,000 individuals were employed as teachers in the 2021/2022 academic year.
According to Freedom of Information figures obtained by Newstalk, 8,871 people who were not registered with the Teaching Council worked 136,109 days in a substitute capacity in primary schools last year.
Meanwhile, 5,145 unregistered individuals worked 91,845 days in a substitute capacity in secondary schools. These figures exclude schools run by Education and Training Boards.
It comes as primary and secondary schools face huge challenges in finding registered teachers to fill in for career breaks and maternity or sick leave.
Schools are entitled to employ unregistered teachers in urgent or unforeseen circumstances, but they are limited to teaching in a particular school for a maximum of five days and are paid an unqualified rate of pay.
Labour's Education Spokesperson, Aodhán Ó Ríordán, says hiring unqualified teachers is damaging to the profession.
"These issues should be well known to the department by now, if they're serious about recruiting and retaining professional teachers in the system."
"We can't stand over a situation where our children are being taught by those who are untrained."
"It undermines the profession, undermines their education. So the department surely should know by this stage, that we have a problem."
The Department of Education says an unregistered person must hold at least a level seven qualification on the National Framework of Qualifications, and any unregistered person who is a teacher must be vetted for child-protection reasons.
