The points required for entry to many third-level courses have risen significantly following the introduction of bonus points for Higher Level Leaving Certificate Maths.
Over 21,500 students of the 50,000 applicants who received offers of a third-level place today have already accepted their first round offers.
Data from the Central Applications Office shows the points rise is strongest in the areas of science and technology.
However, the points requirement for the country's main arts courses has not been affected.
Just over 76,000 people applied through the CAO this year.
CAO Operations Manager Joseph O'Grady said more than 77% of applicants received their first preference courses in the first round of offers, which went out this morning.
Mr O’Grady said that the website was very busy early this morning but was running smoothly.
He added that only around 3,000 students will get a net benefit from the 25 bonus points for Higher Level Maths.
Mr O'Grady explained that as it is only a student’s six best subjects that count towards CAO points, only a minority of applicants, who have performed very well in Higher Level Maths, will actually benefit from the bonus points.
Demand for arts-related courses has fallen by 6%, while science-related courses have seen a 17% surge in interest compared to last year.
The science degree course in UCD has risen by 45 points, while computer science there is up by 60.
Business and finance-related courses have generally seen a significant points rise also.
Trinity College Dublin has called for the points system to be reformed and said it was planning to offer a new entry system to students in September 2014.
Speaking on RTÉ's News At One, TCD's Dean Of Undergraduate Studies Dr Patrick Geoghegan said they would use a number of scales to assess students.
Dr Geoghegan said: "Leaving Cert results would be assessed and analysed, but we'd also be assessing other factors - personal statements, perhaps references from teachers or guidance counsellors. We'd be looking at contextual data."
He said taking a holistic approach to the applications is a more fair assessment, allowing them to match the right students to the right courses.