A processing plant in Co Tipperary has been shut down after inspectors found it was exporting horse meat under a label in the Czech language which translated as beef.
B&F Meats, a small-scale deboning factory in Carrick-on-Suir was selling a mislabelled product to a customer in the Czech Republic through a trader based in the UK.
The Minister for Agriculture Simon Coveney has said that all operations at the plant have been suspended.
He said: "I am seriously concerned about this development and the gardaí have been fully appraised of this development and are working closely with my department."
Minister Coveney said: "The issue here is one of mislabelling and that will be the focus of the investigation."
Officers from the Department of Agriculture's special investigations unit have been carrying out searches at the factory this afternoon.