People who have been in close contact with a male who is the first person to be confirmed with the Coronavirus in the South have yet to all be identified.
But the Department of Health said the tracing process has begun.
Officials from the Department said they had been aware of the confirmed COVID-19 case in the last few hours.
Now the tracing process has begun to make contact with the public who have been in close proximity to the male who is in the East of the country.
The male travelled back to Ireland in the past 14 days from an infected area in Italy.
He is the second person on the island of Ireland to be infected - a Northern Irish woman who was also in Italy and came through Dublin Airport was confirmed to have COVID-19 on Thursday.
Chief medical officer of the Department of Health Dr Tony Holohan refused to say if the case in the North is connected to the first confirmed case in the Republic of Ireland.
Dr Holohan said he would not state what county the man is living in or if he had travelled with anyone else in order to protect his identity.
The general public is advised to follow advice from the HSE and the Health Protection Surveillance Centre to protect their health.
Any person concerned that they may have symptoms of Covid-19 (Coronavirus) should immediately isolate themselves from others and contact their GP by phone.
Minister for Health Simon Harris said he had notified the Taoiseach Leo Varadkar of the confirmed case.
Speaking tonight, Minister Harris said: "This is not unexpected. We have been preparing for this since January.
"I would strongly encourage people to follow the guidance and advice of the National Public Health Emergency Team, led by the Chief Medical Officer."
