A new survey has revealed that primary schools are unable to find adequate cover for one-in-three teacher absences.
The study, undertaken by the Catholic Primary School Management Association (CPSMA), has warned that some vacancies are being filled by unqualified people - while others are not being filled at all.
The CPSMA provides advice and support to management at over 2,800 schools in Ireland.
It said one factor leading to the shortage is the number of teachers who are moving to the Middle East for work - with the price of housing in Ireland contributing to the exodus.
The results appear to contradict comments made by the Minister for Education Richard Bruton a number of weeks ago in the Dáil.
Responding to a parliamentary question on the shortage in supply of substitute teachers at primary level, Mr Bruton said “In overall terms, my Department has no evidence of a recent or current shortage of primary teachers.”
He admitted that some schools were finding it difficult to recruit "adequately qualified substitute teachers" insisting he is "committed to examining all possible means" of tackling the issue.
Seamus Mulcrony, CPSMA General Secretary said the minister's response contradicted the feedback coming from its member schools.
“This survey provides clear and compelling evidence that there is now a nationwide shortage of substitute teachers," he said.
"The shortage is putting huge pressure on principals, negatively impacting on effective administration, training and the adoption new programmes in schools.
“The shortage will certainly, in time, impact on the quality of education being provided to pupils - particularly to those with special educational needs."
The survey found that, in some cases, school principals are being forced to use Special Education Teachers for supervision duties in mainstream classes.
Principals are spending a "significant amount of time" searching for substitute teachers - with educators often forced to work while ill - and cancel service training days - because there is nobody available to cover.
School management is also finding it difficult to cover maternity leave and even fill permanent posts - with positions left unfilled over a number of days and sometimes weeks.
The CPSMA has warned that the shortages are having an impact on children's education - particularly those with special educational needs.
"It is a matter of grave concern that principals are being forced in some cases, as a last resort, to use special education teachers to supervise mainstream classes," said Mr Mulcrony.
"Both the survey and anecdotal evidence from CPSMA suggest that we may be seeing the first indications of a shortage of teachers for full time positions.
"The evidence is in – Government must act swiftly to address this issue.”
The CPSMA is now bringing the survey results to the attention of Minister Bruton and to his department officials.