Organisers of the Ballindenisk one-day event in Co Cork Ireland have launched an investigation after the death of Karen Rodgers at the event on Sunday.
The British-born 41-year-old was killed in a fall while taking part in the CNC** competition with her horse Kilcoltrim Brigade.
The accident took place at the penultimate fence on the course, the second water complex.
Peter Fell, organiser of the event said: “We are deeply shocked by this accident — nothing like this has ever happened here before.
“Our sympathies go out to her family. It’s a very difficult time for everybody.”
Eventing Ireland described Ms Rodgers as “an experienced and successful rider”, who had been involved in equestrian sport in Ireland for 10 years.
Eventing Ireland chairman John Wright said: “Karen was a well-known and popular figure in equestrian circles, and we wish to extend our profound and heartfelt sympathy to her family and friends.”