Due to a fall in the youth population, universities may have increasingly to accept weaker students with lower CAO points, one of Trinity College's senior academics has warned.
In an internal memo, released under the Freedom of Information Act, Prof Michael Laver, the college's registrar until recently and a political scientist, predicted there would be a decline in points for a range of courses, with weaker students able to get places.
The danger however is this could push up failure rates, he said, because statistically those with lower points are "intrinsically more likely to fail".
Trinity is currently studying the problem which will affect all colleges.
The number of people aged between 15 and 24 will fall from about 660,000 at present to 530,000 in 2016, according to figures from the Economic and Social Research Institute.
Prof Laver, in his memo from last year on failure rates at Trinity, said the university sector will have to come up with new policies to deal with the issue.
One option is to accept the increasing failure rates, he stated. "As entry qualifications decline, we might accept that increasing failure rates are an inevitable consequence," said the memo, presented to the college's university council.
Prof Laver added: "We would justify this position by arguing that an increasing number of less well qualified students were being given the chance to succeed at university, although not all of them would prove able to do so."