Australia's horse-racing community was reeling on Tuesday after jockey Simone Montgomerie died after falling during a race at the Darwin Cup meeting.

The 26-year-old, a young mother, was thrown from her mount Riahgrand during race six on Monday as she came down the home straight, and was trampled by other horses.

"Simone fell and sustained traumatic injuries," Darwin Turf Club chairman Brett Dixon said in a statement about the trailblazing female jockey who rode 27 winners for the 2012-13 season.

"It is with great regret that we were advised by the family that Simone passed away shortly after arriving at the hospital."

The rest of the meeting, including the feature Darwin Cup race, was abandoned to allow a full investigation to take place.

"There will be a full investigation, which has already been initiated by the stewards," said Dixon.

"The Darwin Turf Club along with the entire industry offer our deepest condolences and sympathies to the family of Ms Montgomerie."

Champion Nash Rawiller was one of many jockeys who took to social media to express their shock.

"I've never left a racecourse feeling so sad and numb," tweeted Rawiller, who was in Darwin for the Cup.

"Great jockey and beautiful young lady. Thinking of her family and close friends."

Northern Territory Chief Minister Adam Giles said it was a sad day for the Australian racing industry.

"Simone was a champion jockey at the top of her game and a pioneer of women in racing who will be sorely missed," he said in a statement.