University College Cork (UCC) is under pressure to postpone changes to the minimum-entry requirements for a place in the college from 2014.
The Institute of Guidance Counsellors (IGC) has attacked the move and is seeking a meeting with UCC.
UCC took the education community by surprise with its announcement that it was doubling, from two to four, the number of higher level Leaving Cert subjects school-leavers will require.
Although most college entrants are already at that standard, it is seen as a challenge to weaker students.
The Department of Education is among those taken aback by the move, and particularly due to its timing, as wider discussions are under way about reforming the system for college entry.
The department has written to the Irish Universities Association expressing its concern.
Now the IGC, which represents guidance counsellors in second-level schools, is also taking the matter up.
IGC spokesperson Betty McLaughlin said: "Our views were never sought on this and we have a close working relationship with all the colleges."
She said guidance counsellors had only received the notification from UCC when schools re-opened for the new term.
Ms McLaughlin said the notice was far too short for students sitting the Leaving Cert in 2014. She said it was practice to have a two year lead-in to such changes to allow students to make the necessary preparations.
She said, under the terms of a long-standing agreement between the IGC and the colleges, such a change should only be introduced for those starting fifth year in 2014.
UCC registrar and senior vice-president for Academic Affairs Professor Paul Giller said the measure was an effort to address educational standards and represent a more realistic description of the minimum level of attainment in the Leaving Certificate necessary to succeed at UCC.
He said there were good reasons for this, as students without the necessary levels of education and associated knowledge, skills and competency were likely to struggle in the first year and have a significantly higher risk of failure.
Although UCC comes under the umbrella of the National University of Ireland (NUI), along with UCD, NUI Galway and NUI Maynooth, it has acted alone on this issue.