About 100 students in Queen's University halls of residence in Belfast have been told to self-isolate after 30 people tested positive for Covid-19.
A spokesperson for Queen's said "robust protocols" were in place to minimise further spread.
Queen's University Belfast (QUB) runs a number of large accommodation sites in Belfast.
It has halls of residence in the city centre and on the city's Malone Road.
There are around 3,000 people across all QUB accommodation in Belfast.
First Minister Arlene Foster has said the Executive Office will hold meetings with NI's two universities tomorrow (on Tuesday) to discuss coronavirus issues involving students.
She said she noted that some students at Queen's University were self-isolating and that she sent them her "best wishes".
"I hope it doesn't become wider spread," she said.
"There are many scare stories about universities and our young people but I believe in our young people - I believe on the whole they want to do what is right and I'd appeal to them to abide by the regulations."
She added that she believed that the police presence in the Holyland area of south Belfast had helped with enforcement issues of the Covid restrictions there.
"It's important we continue to try and work with our young people to get the message to them," she said.
Are you a student in Queen's University halls of residence? Have you been told to self-isolate?
Queen's University has not said which site is affected, but BBC News NI understands students in one specific accommodation block at the Elms site on the Malone Road have been asked to self-isolate.
It is also believed the number of students who have been asked to self-isolate is fairly small and in double figures, rather than in the hundreds.
Tom Rhydderch is from Wales, but is 11 days into isolation at Queen's Elms accommodation.
He said: "We're not allowed outside and we're walking up and down the corridor for exercise.
"We get food deliveries left on the stairs. Lots of oven pizza."
A spokesperson for QUB said evidence suggested transmission of the virus was "taking place in social settings".
"The university can confirm that a small number of students living in Queen's accommodation have tested positive for Covid-19," they said.
"The university is working closely with the Public Health Agency and in line with their guidance all affected students or those who are considered to be at risk have been informed, asked to self-isolate and are being fully supported to do so.
"The university has in place robust protocols to minimise the risk of further spread that are being applied."
"All other students and their families should remain calm and continue to follow public health guidelines to protect themselves and others."
A Covid-19 testing centre at QUB is now in operation close to the university's physical education centre.
Students have been told to isolate in their accommodation at several universities in England and Scotland.
By Michael Sheils McNamee, BBC News NI
The student accommodation of Elms Village sits back from the desirable Malone Road in south Belfast.
Despite some students testing positive for Covid-19 and others having to self-isolate, the mood around the building was far from panicked on Monday afternoon.
Students walked in and out of the halls in ones and twos, making the trip to the Queen's campus half a mile up the road.
Stopping to speak, a few said they had heard about the outbreak in the building but weren't too worried about it.
While those locked in their rooms are set to face a tough couple of weeks, for most of the residents it seems to be business as usual.
The new university year at both QUB and Ulster University began on Monday 21 September.
Many students are taking a significant proportion of their courses online with students taking degrees which involve practical or laboratory work most likely to spend time on campus.
There are also many safety measures in place, including extensive use of face coverings.
However the University and College Union (UCU) at QUB - which represents many staff - has said it is unhappy with the extent of face-to-face teaching taking place.
Meanwhile, the number of coronavirus-related deaths in Northern Ireland remains at 578, according to the latest Department of Health statistics.
There were no further deaths reported by the department on Monday.
The total number of cases in the past 24 hours increased by 220, with the total number of people testing positive now 10,949.
The Department of Health in the Republic of Ireland announced an additional 390 cases on Monday. bringing its total to 35,377 confirmed cases.
It reported no further deaths with the death toll remaining at 1,802.