The Department of Defence has requested all animals on the Curragh, Co Kildare, be removed from the land as fears rise that the risk of foot-and-mouth disease could spread into the Republic.
A Department spokesman told ireland.com: "This afternoon owners of sheep herds and members of the racing community who exercise their horses on the Curragh were asked to take their animals off the land immediately."
The decision was made on the advice of the Department of Agriculture chief veterinary officer.
Turf Club and Curragh racecourse press officer Michael O’Rourke confirmed restrictions had been put in place in the Curragh area.
"We have received an instruction from the Department of Defence, who completely control the military training grounds around the area, that it is no longer permissible to exercise racehorses on the Curragh as they may come in contact with sheep."
"At the moment the situation remains open ended . . . the fact that horses can not race is bad enough but trainers not being able to train their horses is a very serious matter indeed."
Turf Club chief executive Brian Kavanagh explained what effect this may have on the racing industry.
"The case of not exercising horses is a short-term problem and one that can be overcome but there is a big concern that the horses can come into contact with the sheep on the Curragh."
"But in the long term this could be a huge welfare problem as 12,000 race horses, that is 25 per cent of the total trained in the country, need exercise of some sort."
While racing in Ireland has been postponed for the foreseeable future, the Curragh racecourse is not due to stage its first meeting of the year until March 25th.