Labour's education spokesman Aodhán Ó Ríordáin has said any school profiling element in calculated grades could 'doubly disadvantage' an already disadvantaged student.
He said the Government has to be ready to act over any potential issues with the calculated grading system.
It comes after the Scottish government apologised to students there over downgraded exam results.
Scotland's First Minister Nicola Sturgeon admitted her government did not get it right over local exam results, amid concerns that pupils from poorer areas were unfairly affected by a moderation formula to calculate final results.
With no central exams there because of the COVID-19 pandemic, similar to Ireland, teachers graded pupils and the grades were then moderated by academic boards.
Deputy Ó Ríordáin told Newstalk Breakfast: "All through this process, right from the beginning, we have raised concerns about the model of assessed grades that the Government are employing - particularly the school profiling element.
"But we have been assured and reassured all through the process that there isn't a cause for the concern that we have raised.
"We have felt that when you take a schools profile into consideration, that is potentially doubly disadvantaging an already disadvantaged student.
"What's happened in the Scottish situation is not just that a huge number of students had their exam result suppressed, it was disproportionately disadvantaged students had their exam result suppressed.
"On that basis there's two things we need the [education] minister to do.
"One is to come out today and reassure students that the Irish model will not follow what the Scottish model did; but secondly, if it does happen, that there's going to be a very robust appeals mechanism put in place to ensure that we can correct it.
"In fairness to the Scottish system, even though they gave all the reassurances that were given in Ireland, the first minister has apologised and says they're going to try and correct it".
"I really hope I'm wrong - and we really hope that we're wrong - but on the 7th and 8th of September if it turns out that we're right, Government have to be in a position to correct it".
Deputy Ó Ríordáin said the appeals process will only go so far.
"There's an appeals process that only affects the way the exam result was arrived at - basically the totting up of the numbers, not the actual grade itself, this is the issue.
"You can only appeal the mechanics rather than the grade, and that's a difficulty that students are going to have.
"We have a particularly unequal education system in Ireland.
"We have a huge number of students in disadvantages schools who are studying higher-level subjects outside of their own school system because the school doesn't offer higher level subjects.
"These students are potentially going to be really hampered by this system".