A number of colleges have defied a CAO recommendation by cancelling courses shortly before CAO offers were announced.
Distressed students told The Irish Times that they were devastated to learn on the day offers were issued that the courses they had chosen had been withdrawn.
The Union of Students in Ireland has accused the colleges of "playing Russian roulette with students' futures".
The institutions involved include Dublin City University, Dublin Institute of Technology, Carlow Institute of Technology and the National College of Ireland.
All third-level institutions have been advised by the CAO to make their final decisions on whether to offer courses by May 1st, in time for students to be informed by their guidance counsellors, so that they can change their CAO application forms. The deadline for filling in the "change of mind" form is July 1st.
Universities are supplied in March by the CAO with student preferences for their courses. However, some universities and institutes have been waiting to see applicants' Leaving Cert results and to preview students' other CAO offers before withdrawing courses. This is too late for students to change their CAO applications.
"Some students have been left with no college place at all. Others are disappointed not to get the chosen course they have been working towards for a year," according to the USI president, Mr Will Priestly.
For the second year in a row, the NCI withdrew NC 002, European business with a language. The degree course was cancelled because not enough eligible students applied for it through the CAO, making the course economically unviable, according to the college. Ms Irene O'Gorman, director of marketing for NCI, stated: "It was our intention to run this course, and we are very, very sorry it has been withdrawn. But we had no choice and there is nothing we can do."
Dublin City University withdrew a course in Applied Computational Linguistics, DC 122, when they considered the numbers of eligible students to be insufficient.
This is the second year running that DCU has been criticised. Last year it was accused of artificially raising points on a computers course.
DIT cancelled two courses: FT 256 and FT 257, Business Studies with French and Business Studies with Spanish.
Carlow Institute of Technology cancelled CW 100, International Business with French, a degree course, and CW 094, Computing Wexford, a diploma course.
Ms Mary Jordan, academic administrator and student affairs manager, explained that "when we looked at the eligible applicants on Monday [August 18th] we realised that we would not have a viable course."
In contrast, the Institute of Technology Sligo withdrew a course, SG 341, before the change of mind deadline and wrote individually to each applicant offering them alternatives.