Up to 80 children with special needs in the Dublin area alone do not have a school place to meet their assessed needs from next September.
It is estimated that dozens of other children outside the capital also do not have appropriate school places to meet their needs.
However, there is no centralised data available yet on the number of children nationally without such places.
The shortage of special needs education places was the subject of political debate on Wednesday after Taoiseach Micheál Martin apologised to a family who have been without appropriate education for their children for seven years.
On Tuesday evening, RTÉ's PrimeTime featured the story of Gillian and Darren Milne who have struggled to find support for their twin sons Ryan and Kyle (11), who have autism.
The boys’ parents have been pleading for the State to intervene and provide places for their twins in a special school.
"The State has failed the Milne family," Mr Martin said in the Dáil.
Mr Martin said that with a quarter of the Department of Education’s budget focused on special education , the problem was an issue of “matching resources to needs”.
He said the capacity of special schools needed to be increased, while stronger legislation was needed to ensure it “no longer can it be an option that schools don’t take in a student with special needs”.
In a statement on Wednesday evening, Minister of State for Special Education Josepha Madigan pledged to ensure every child with special educational needs had access to a school place.
She said there were areas, mainly in Dublin and Cork, which had higher numbers of children with special educational needs who were waiting for a school place.
She confirmed that she plans to issue to section 37a notices to schools – which require them to enrol special needs pupils – in areas that desperately require additional special education places.
Ms Madigan said the 80 children without special school places in Dublin is likely to fall as authorities engage with schools.
Adam Harris, chief executive of the autism charity AsIAm, said access to a school place is a child's constitutional right.
“I think in discussion around autism, the Department of Education frequently cites the levels of investment – but the real key performance indicator is whether every child has a school place, in line with their constitutional right,” he said.
"We don't have that data because of the failure of the Department and the National Council for Special Education (NCSE) to collate it. From our own research, we have estimated that up to 26 per cent of families of children with autism do not have an appropriate school place."
He also pointed to the fact that 1,400 children are in receipt of home tuition, many of whom cannot access an appropriate school place.
Mr Harris called on the Minister to direct the NCSE to establish a national database to establish the true scale of school place shortages and to focus more on forward planning.
“We have to recognise that some children have been waiting seven years for appropriate school paces,” he said.
“During that time, much of the NCSE’s focus was on moving away from a policy of special classes and special schools, even though the education system wasn’t equipped to meet children’s needs. This has been a period of lost time and opportunity.”
He also said the “vast majority” of children who need a special class at primary level need it at second level, and called on authorities to ensure planning for this is stepped up.
