A group of Queen's University students deemed "high-risk" will undergo a period of isolation after a student tested positive for coronavirus, the pro-vice chancellor has said.
Prof Stuart Elborn said anyone who may have had contact with the individual has now been contacted.
It brings the total number of cases in the region to three - none are linked.
Across the UK, the total number of positive tests has risen to 90, and health officials have moved into the second phase of their response to the coronavirus outbreak.
Prof Chris Whitty, the UK's chief medical officer, has said it is "highly likely" there is now some "community transmission" within the UK.
Measures would be ramped up to slow the spread of the virus and could involve "changes to society", he said.
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The Queen's University Belfast (QUB) student had recently returned from northern Italy and had been mixing with others at university.
The other adult had been in contact with someone in the UK who had tested positive for Covid-19, the respiratory disease caused by the virus.
Prof Elborn said "appropriate cleaning" had taken place in the areas where the student was present.
"At this moment there is no need to close anything or halt any particular activities," he said.
"We will be keeping a very close eye on a daily basis as to how this develops.
"And we will make decisions in the university in line with what we need to do to protect society in Northern Ireland and more widely in these islands."
Queen's said its major incident team had been convened and was putting in place the appropriate contingency measures.
"There will be a helpline [on Thursday] and I will be meeting with the particular school where this occurred later to have an opportunity to discuss this with the students and the staff," he said.
Four new cases were confirmed in the Republic of Ireland on Wednesday, bringing the total number of cases there to six.
The patients, two men and two women, all travelled from the same affected area in northern Italy.
Ireland's deputy chief medical officer Dr Ronan Glynn maintained there was "still no evidence of widespread or sustained community transmission in Ireland, as seen in some other EU countries".
The first case in Northern Ireland was a woman who had travelled to northern Italy, which is at the centre of the European outbreak.
Northern Ireland's chief medical officer Dr Michael McBride said the latest two patients were receiving the appropriate care and officials were working to identify anyone they had come into contact with.
Northern Ireland remained in the containment phase, he added.
In other developments:
- Stormont will look at plans for "all large-scale events" but the chief medical officers believes it is too early to make any decisions
- The chief medical officer advises against wearing face masks as hand washing is a more effective deterrent
- Belfast City Marathon organisers say they have no plans to cancel the event yet but are working on measures to reduce risk
- Northern Ireland's tourist industry is to hold an "urgent coronavirus summit"
- Ireland's chief medical officer Dr Tony Holohan says the St Patrick's Day parade in Dublin on 17 March does not need to be cancelled "as things stand"
- Finance ministers from the UK's devolved administrations will meet with Chief Secretary to the Treasury Stephen Barclay to discuss extra health funding
- UK Prime Minister Boris Johnson says workers will get statutory sick pay from the first day off work to help contain coronavirus
- The First and Deputy First ministers Arlene Foster and Michelle O'Neill cancel the New York leg of the US trip due to coronavirus.