Queen’s University (QUB) has launched an investigation into what it has called “irresponsible and reckless behaviour” by some students in its halls of residence.
In an email to students, the university said “disciplinary measures” could result.
The investigation involves allegations over a party breaching Covid-19 guidelines, BBC News NI understands.
It took place in an area of the Elms BT9 student village on 1 October.
In a statement, QUB said it was “aware of a video showing students on university premises breaching public health guidelines, putting their safety and the safety of those around them at risk”.
On Monday 28 September, QUB said about 100 students in the halls of residence had been told to self-isolate.
That came after about 30 students living in the Elms halls had tested positive for Covid-19.
Elms BT9 is an extensive site on Belfast’s Malone Road, about 10 minutes walk from the university campus.
It is run by QUB and houses mainly first-year undergraduate students.
The email to students from the QUB registrar Joanne Clague was titled: “Student breaches of public health guidelines”.
Ms Clague thanked students who had followed Covid-19 guidelines “despite the current challenges and restrictions that we are all having to live with”.
“I know that this has required many of you to make sacrifices at the start to the academic year and I applaud your maturity and responsibility in doing so,” she said.
However, Ms Clague said the university was aware of a “small group” of students in university accommodation who had failed “to act responsibly”.
“This irresponsible and reckless behaviour is putting the health and wellbeing of other members of the Queen’s community at risk and cannot be tolerated,” she wrote.
“An investigation has been launched and disciplinary measures will be applied robustly in line with the student code of conduct regulations.
“Many of you will be aware of circumstances in other universities where access to facilities and the freedom of students in university accommodation has been curtailed to mandate adherence to public health guidelines,” Ms Clague continued.
“At Queen’s, we have respectfully chosen to treat our students as independent adults in the expectation that they act responsibly.
“It is very disappointing that some students appear to have abused that trust.
“A number of interventions have been made immediately to ensure a similar situation is not allowed to happen again.”
Ms Clague also wrote it was “with regret” that Queen’s had to discipline some students for off-campus behaviour.
“Some of the commentary and coverage of students in recent weeks has not been representative of the broader student body,” she continued.
“This makes it all the more disappointing when the university is forced to take action that affects all of you because a small proportion of students have not acted appropriately.”
Ms Clague concluded the email by saying if public health guidance was not followed by everyone, tighter restrictions were “inevitable”.
A number of universities across the UK have seen significant numbers of Covid-19 cases despite many degree courses being taught mainly online.