The Department of Education has told schools it is to cut the number of English Language Teachers by 250 from September.
That is double the cut that schools had expected.
A Department spokesperson said the number had been doubled to enable the system to comply with the Employment Control Framework, which restricts numbers working in the public sector.
The move will affect primary schools most.
The Irish National Teachers' Organisation has said the decision is another attack on disadvantaged and marginalised children.
The INTO also said the decision flew in the face the Government's commitment to improve literacy standards in schools.
An OECD report last year found a dramatic fall in literacy standards in Irish schools.
English language teachers are employed in schools to help children from International backgrounds who cannot speak English or whose English is too weak to enable them to thrive in the classroom.
The 250 posts represents a cut of 18% to the number of language support teachers currently working in the system.
There are currently 1,400 posts dedicated to supporting children whose English is weak and 80% of these posts are in the primary sector.
The previous Government announced a cut of 125 to be implemented in September and by the same amount annually for three years.
However, a spokesperson from the Department of Education said it was now necessary to speed up the process in order to meet the needs of rising numbers of children in the education system.
