The total number of Covid-19 cases in the UK has risen to 16, after three people were diagnosed on Thursday.
The first positive test for coronavirus in Northern Ireland was confirmed at a briefing in Belfast.
The patient had recently returned from northern Italy and had previously been in Dublin.
Another of the new cases, a parent at a Buxton primary school in Derbyshire, contracted the virus in Tenerife, where 168 Britons are being kept in a hotel on the south west of the island.
The third patient also contracted the virus in Italy, which has become the worst affected country in Europe with more than 400 cases and 14 deaths.
Speaking at the Belfast press conference, Dr Michael McBride, chief medical officer for Northern Ireland, said the test outcome has now been sent to Public Health England laboratories for verification.
“We have robust infection control measures in place which enable us to respond immediately.
“Our health service is used to managing infections and would assure the public that we are prepared.
“Our advice to the public remains the same.
“Members of the public who have visited affected regions and have symptoms are advised to self-isolate at home and contact their GP in the first instance.”
A special unit has been established at the Royal Victoria Hospital in Belfast for isolating those suffering from the virus but the health authorities were unable to confirm where the patient is being treated.
One of the patients in England has been taken to the specialist infectious diseases centre at the Royal Liverpool Hospital and the other to the Royal Free Hospital in London.
In Derbyshire, Burbage Primary School in Buxton remains closed after a parent there was diagnosed with the illness.
He added: “Close contacts will be given health advice about symptoms and emergency contact details to use if they become unwell in the 14 days after contact with the confirmed cases.
“This tried and tested method will ensure we are able to minimise any risk to them and the wider public.
“We are aware that Burbage Primary School in Buxton has taken the decision to close today.
“My team have spoken to the school, assessed the risk and confirmed that there is currently no information to suggest that there is any increased health risk to any pupils or staff at the school and no public health reason to remain closed at the current time.”
Buxton Medical Practice in Derbyshire, a two-minute drive from the school, also urged patients not to attend for appointments on Thursday due to the confirmed case.
Sources told the PA news agency that around 50 of the Britons will be allowed to leave if they wish.
The Minister of Health in Tenerife said around 130 of guests from 11 different countries will be able to leave the hotel if they arrived on Monday, after infected guests had already left.
Meanwhile, two Britons were among eight people being monitored on board a cruise ship that was turned back by the Dominican Republic.
A joint statement by the Public Health Ministry and Port Authority on the island said the captain of the Braemar, which is carrying around 1,500 people, reported four Filipinos, two British citizens and two US citizens were under medical observation for symptoms such as fever, coughing, or breathing difficulty.
It comes as England’s chief medical officer, Professor Chris Whitty, warned that onward transmission between people in the UK was “just a matter of time in my view”.
So far in the UK, 7,690 people have been tested for the virus and of the 16 to have tested positive, eight have so far been discharged from hospital.
In China, where the virus originated, 78,497 cases have been reported, including 2,744 deaths.
World Health Organisation (WHO) director-general, Dr Tedros Ghebreyesus, told a press conference in Geneva on Thursday that coronavirus has the potential to become a global pandemic but this stage had not been reached.
Public health advice remains to wash hands with soap, not rub the face and maintain a distance from people who are coughing and sneezing, he said.
