Health officials say people from the north have been diagnosed with and treated for the Zika virus.
Fewer than five people have been treated in the north's health trusts, according to the Public Health Agency.
It is believed that one person was treated as recently as last week.
The agency said there was no specific treatment other than supportive measures including hydration for those with symptoms.
The virus is mainly spread by mosquito bites and evidence of the risk of birth defects and other complications in infants born to infected mothers is growing.
The World Health Organization has declared Zika a global public health emergency.
The Zika virus was first discovered in 1947 in Uganda.
A new international research project to tackle the virus announced last month, will be led by an expert from Ulster University.
Professor Helen Dolk, a world-leading congenital anomaly expert, is working on two programmes to gather and analyse data on cases of Zika.
