The Department of Agriculture has confirmed it is investigating an alleged case of the use of the growth hormone, Clenbuterol, in cattle.
It follows a report in the Sunday Times that the drug was found in a cow at a meat plant.
The report says follow up searches resulted in a seizure of Clenbuterol at a farm in Co Monaghan.
The department said the investigation follows from a positive result for one animal in a random sample taken as part of the National Residue Control Programme.
It added that it has put all animals on the farm under restriction, pending the completion of the investigation and "the Food Safety Authority of Ireland is fully aware of the case and has concluded that there is no risk to public health from meat that is on the market."
Former agriculture minister Simon Coveney said he believes this shows that the department's testing regime remains vigilant and should pick up any wrongdoing very quickly.
He added that he did not want to pre-judge the case, which is still under investigation, but hoped the department would be able to get to the bottom of the case quickly and restore full confidence in the markets in Irish beef.