Mikaela Claridge returned to riding in 2018 and won her first race in September
Melbourne - Racing Victoria said a planned eight-race card at nearby Pakenham would not be held on Friday
Racing Victoria said on Friday that the early-morning accident happened at the Cranbourne track, about 50 kilometers (30 miles) southeast of Melbourne.
It said track work was cancelled after the death of the jockey, Mikaela Claridge. "Mikaela was dislodged from her horse while riding on the sand trails on the southern side of the Training Centre at approximately 4:35 a.m. She was attended to by the on-course paramedic but was tragically unable to be saved," Racing Victoria said in a statement.
After injury interrupted her career, Claridge returned to riding in 2018 and won her first race in September. She had since won 28 more races, the most recent on July 11.
Racing Victoria said a planned eight-race card at nearby Pakenham would not be held on Friday.
"The meeting has been abandoned in the interests of participant welfare and out of respect for the rider and her family," Racing Victoria said.
Australian horse industry figures show 20 jockeys have been killed in the country since 2000, 17 of them during races and three during track work. In February, a Victoria state trainer died, also after falling from a horse during a training run.