Avian flu has been detected in a "small free range turkey flock" in Co Wicklow, the Department of Agriculture, Food and the Marine has confirmed.
Further testing to determine the pathogenicity is being carried out and results are expected over the coming days.
The birds have been killed and avian influenza restriction zones with additional protection and surveillance measures are being put in place.
Highly pathogenic Avian Influenza H5N8 had already been confirmed in wild birds in a number of counties across the country.
The department said the findings "pose a risk to all poultry flocks and captive birds and by extension the poultry industry".
Outbreaks of highly pathogenic avian influenza have also been identified in poultry flocks in Britain, Netherlands, Germany, France, Denmark, Sweden, Poland, Croatia and Ukraine in recent weeks.
In a statement, the department said: "It is important to note that there is no evidence of risk associated with consumption of poultry meat or poultry meat products.
"The Health Protection Surveillance Centre has confirmed that although the H5N8 subtype can cause serious disease in poultry and other birds, no human infections with this virus have been reported worldwide.
"Therefore risk to humans is considered to be very low.
"Poultry flock owners should remain vigilant for any signs of disease in their flocks, maintain strict biosecurity measures and report any disease suspicion to their nearest regional veterinary office."