British jockey Kieren Fox has avoided injury after a bizarre incident involving a golf ball in the opening race at Sandown.

Fox hit the deck inside the final half-furlong (100m) of the maiden after his mount Luxford veered right, leaving him with little chance of staying on.

On closer inspection of a replay, the two-year-old filly had become distracted by a stray golf ball on the course which appeared to be thrown up by eventual winner Big Lachie, before ricocheting off the helmet of another rider and across the sightline of Fox's mount.

"The five-furlong course is situated alongside a golf course and the area in question is near a par three hole," clerk of the course Andrew Cooper said.

"We have a 14-strong team that walk the course, and other parts of the track, looking for golf balls as golf is played here year round other than on days when racing takes place.

"From my experience, even with that many people doing checks on the course, unless they see or tread on a golf ball there will be golf balls buried on the course."

"The horse and rider are fine and the stewards' looked into it and after talking to me and hearing the explanation of the routine we take they have treated it as accidental."

The afternoon ended on a more positive note for Fox after he won a race later on the program.