A third outbreak of avian influenza, or bird flu, has been confirmed on a commercial turkey farm in less than a week.
The latest cases were detected in a flock near Clontibret, Co Monaghan, close to the border with Northern Ireland.
It is understood the farm is a significant operation, with thousands of turkeys - all of which will be culled due to the outbreak.
A 3km protection zone and 10km surveillance zone are in place around the site.
The location is a particular concern for officials, given there is a high concentration of poultry farms in the border region in counties Cavan and Monaghan.
It comes after two bird flu outbreaks were detected last week on commercial turkey farms - one in Carlow on Tuesday, with another near Kells in Co Meath on Wednesday.
A housing order for all poultry and captive birds in the country is in effect from today due to the heightened risk from the virus.
A similar measure has been in place in Northern Ireland since Thursday.
Minister for Agriculture, Food and the Marine Martin Heydon said the outbreak underlines the "ongoing risk to poultry and captive birds of avian influenza".
"We know the virus is circulating in wild birds across the country. The compulsory poultry biosecurity regulations and housing order, which I have introduced, will help to mitigate the ongoing risk, but a strict and meticulous attention to biosecurity by all those who keep poultry or captive birds is the best way to protect our flocks from further outbreaks during this very challenging higher risk winter period.
"I want to express my sympathies to the flock owners who have been affected by these outbreaks, and to thank poultry keepers nationally for their continued cooperation and strong commitment to maintaining the highest standards of biosecurity."
The Department of Agriculture has called on flock owners to maintain their vigilance around biosecurity on farms, while members of the public are advised not to touch any dead or obviously sick birds they encounter and report incidents via the Department's Avian Check app or by calling the National Disease Emergency Hotline on 01 492 8026.
Read more: Will bird flu mean there won't be turkeys for Christmas?
