The Longines Irish Champions Weekend and Listowel Harvest Festival will both take place behind closed doors, Horse Racing Ireland has confirmed.
Irish Champions Weekend is due to take place at Leopardstown on Saturday, 12 September and the following day's action is at the Curragh.
As a result of the decision to run the event behind closed doors due to uncertainty surrounding Covid-19, all those who purchased early-bird tickets will be refunded.
"We had dearly hoped that circumstances would allow us have racegoers back on the racecourse for Longines Irish Champions Weekend, but that doesn't look at all likely so it is best to make a call on it now," said Longines Irish Champions Weekend committee chairman Harry McCalmont.
"It is a great pity, but we still have a wonderful weekend of racing to look forward to."
Meanwhile, the seven-day Listowel Harvest Festival, which will run from 20 to 26 September will also go behind closed doors.
"In these unprecedented times, and in line with Government guidelines, the Listowel Race Company has made the extremely difficult decision to race behind closed doors, this means the event will not be open to the general public this year," said chairman Pat Healy.
"The health and safety of everyone is our number one priority and with crowd restrictions in place, it would be very difficult for us to run the festival, as it attracts significant numbers of visitors to Listowel each year."