The CAO says it will do it's best to accommodate students impacted by the errors in the calculated grades system, but that many courses are already at a squeeze point.
6,500 thousand students had their marks downgraded due to mistakes within the algorithm.
The Education Minister will address the Dáil this afternoon after promising no student will be disadvantaged by the revelation.
She said there were two errors in the computer code used to generate the marks.
Speaking this morning, Minister Norma Foley said it will be a number of days until the students who have been impacted are informed.
Meanwhile the deadline for applying to sit an exam in November has been moved from tomorrow, with a new closing date to be confirmed soon.
Chair of Board of the CAO and Deputy President at NUIG is Pól Ó Dochartaigh.
He says it's not as simple as adding another place onto a course;
"We've already added half a dozen in medicine and that is actually a squeeze point and I know other universities have added some" he said.
"One of the issues with those kind of courses frankly is that there are requirements then on the hospitals up and down the country for the placements over the next five years, that they get the clinical experience, otherwise their degrees are not going to be recognised."
A helpline for Leaving Cert students has been opened on 01 889 2199.
