The Health and Safety Authority (HSA) has been called in to inspect 31 primary and post-primary schools since the start of this year, it has emerged.
Figures obtained by the Labour Party show that 19 primary and 12 post-primary schools have been investigated.
The figures are a "shocking indictment" of the working conditions faced by staff and pupils in schools, the party's education spokeswoman, Ms Jan O'Sullivan, said last night.
"The inspections would usually be instigated by complaints from teaching staff about their working conditions and those of their pupils," she said.
The Department of Enterprise Trade and Employment said the inspections involved reviewing workplace conditions for teachers and ancillary staff and other workers.
Last week, the Labour Party published its own survey of primary schools which showed that many teachers and staff are operating in cramped, dilapidated and sub-standard buildings.
The INTO last night warned that the HSA inspections were "only a drop in the ocean".
"The INTO has been calling for the HSA to go in and examine schools and see at first-hand working conditions faced by teachers and pupils," the union's general secretary, Mr John Carr, said.
"We would like to see HSA doing a lot more such inspections."
Meanwhile, a conference in Cork at the weekend warned that school principals needed to put comprehensive safety statements in place in order to reduce the risk of being sued by pupils, teachers and other employees.
Mr Geoffrey Shannon of the Law Society warned delegates at a Schools, Education and the Law Conference that safety statements should be subject to periodic review in order to address either legal standards or practical issues that arise within the school.
He said it was important for the safety statement to cover occupational matters such as stress, bullying, harassment, fatigue and eyestrain.
It should also draw the attention of teachers and pupils to their own responsibilities and cover the health and safety of school visitors.