At least 10 per cent of all courses offered through the Central Applications Office (CAO) are expected to have unfilled places when updated statistics are published later today.
In a development labelled as "unprecedented" by one career guidance expert, the general manager of the CAO, Ivor Gleeson, confirmed that it was aware of 138 courses with vacant places by late yesterday afternoon.
This indicates that there are now a record number of unfilled places on courses, with many colleges struggling to fill vacant places due to a smaller student pool and more courses being offered.
According to the Qualifax national course database, there are 1,128 courses offered through the CAO. This means that more than one in 10 of all courses offered through the CAO will have unfilled places.
It is possible that the figure of 138 could rise even further by the time the CAO publishes full details on its website this afternoon.
It is expected that ordinary level degrees and certificate courses will be among those with the highest number of vacancies, although higher level degrees, particularly in engineering and the sciences, will also feature.
Irish Timescolumnist and guidance counsellor Brian Mooney said the figures showed that unlike a few years ago, colleges were now "at the mercy of the student choice process".
There were 79 courses with unfilled places listed on the CAO website yesterday. This list does not take account of courses with vacancies since the Leaving Certificate results were made available last week, or those courses which may have since filled places.
However it does show a number of universities, institutes of technology (ITs) and private colleges with vacant places on higher and ordinary degrees and certificate courses.
According to the list, DCU had vacant places on nine higher degree engineering courses, including its common entry courses in engineering and electronic engineering.
There were vacancies in a number of private colleges, including courses in accounting and finance and computing science in Griffith College, law and marketing in Portobello College and business at Dublin Business School.
Tipperary IT had vacancies on 12 courses, while Galway-Mayo IT had vacancies on 11 courses.
Separately, the CAO said there was a record level of activity on its website yesterday, with 12,427 acceptances logged by 5.30pm yesterday evening.
It expected the number of online acceptances to surpass last year's figure of 14,000 by the end of the day. A spokeswoman said there were no major delays.
Students have until close of business today to submit their applications to have exam scripts reviewed, a spokeswoman for the State Examinations Commission said yesterday.
Meanwhile, the University of Limerick said more than 300 people had applied for its new graduate entry course in medicine, with 30 students due to commence the four-year programme next month.