Northern Ireland students need higher A-level grades for a place in some popular courses at local universities than students from Great Britain.
For example, NI students need three A-levels for law at Queen's University. GB students need three Bs.
The college's compensation website lists the courses and qualifications required by the student's hometown.
Queen and Ulster Universities said this was due to a cap on the number of NI / EU Students.
Compensation is where applicants are assigned to university places that have not been filled.
On the QUB compensation website, students from Northern Ireland who want to study Politics, Philosophy and Economics need three As, while those from Great Britain have been told they can enter with two As and one C or three. Bs.
In a statement, QUB said that the Northern Ireland Assembly establishes student number controls for NI and EU students attending Northern Ireland universities because tuition fees are partially funded by the Department of Economics.
This is known as the maximum number of students limit: the MaSN.
"The MaSN does not include international students or students from England, Scotland, Wales and the Isles (GB), whose tuition fees are not funded; these students are admitted in addition to the MaSN cap.
" Therefore, these places do not displace local or EU students.
"Since there is no specified limit of places for GB or international students, more GB and international students may apply through compensation. Consequently, a greater degree of flexibility can be exercised in terms of accepted qualifications, although the quality it is still high. "
QUB said that NI and EU students with offers may also be admitted with slightly lower grades than specified, subject to availability of places.
The situation was "fluid", they said.
The University of Ulster said the situation was on edge. He said the offers for GB students were separate from the maximum number imposed on Northern Ireland students by the government.
"Places offered to English, Scottish and Welsh students will not displace or harm any student from Northern Ireland," the university said.
"The combination of international and British students studying, living and working alongside local students enhances the student experience and builds a diverse student community.
But Ellen Fearon, President of the National Student Union and the Union of Students in Ireland, said it was the government's responsibility to ensure that anyone who wanted to study locally has a good chance.
"The number of people from Northern Ireland who can go to university here is limited", he said.
"This means that, every year, thousands and thousands of students who applied to study in the north end up leaving the country to study elsewhere and research has found that two-thirds of them never return." he said.
"If the government really wants to invest in the future of Nort hern Ireland, they should prioritize education and make sure that any Anyone who wants to study here has the opportunity to do so. "
The fee system means that GB students pay much more for their degree than those from Northern Ireland or the rest of the EU.
NI students pay £ 4,395 for an undergraduate course, while GB students pay £ 9,250.
International students can pay from £ 16,900 to £ 41,850 per year.
The Queen's University of Belfast (QUB) has already offered guaranteed places to about 2,500 students from Northern Ireland before they received their A-level results.
The university said the "unprecedented step" would "reduce anxiety and bring clarity to youth."
These locations account for approximately 70% of QUB's 2020 NI college student admissions.
Following the QUB decision, Ulste r University said it will also guarantee locations where appropriate.
Both Queen and Ulster universities had previously said they could face losses of several million pounds due to the coronavirus pandemic.
Level A exams were canceled in Northern Ireland, Wales and England in 2020 with results based on "calculated grades" in place.
Level A results will be awarded on Thursday.