On the verge of a successful career, Claridge, 22, died from undisclosed injuries suffered when she fell from her horse on Friday morning.

Victorian Jockeys Association president Matt Hyland said it was too soon to speculate on the cause of the fall on the sand trails at Cranbourne shortly after 4.30am.

"Mikaela was an extremely popular girl and she was embarking on what was going to be a successful career, and she was just finding her feet and getting going," Hyland said.

"It's just an incredibly sad day.

"As we're aware it was a track accident this morning at Cranbourne and the details of that are yet to play out."

Claridge, who was married in March, resumed her apprenticeship in 2018 after a series of injuries and won her first race in September last year.

She had transferred to trainer Ken Keys at Cranbourne and won another 28 races, most recently at Sale on July 11.

Her first trainer, Echuca-based Donna Gaskin, said Claridge had become like part of her family.

"Mikaela was just a lovely little kid," Gaskin said.

"I know, 22, yeah you're a young lady but to us like she was just part of the family. Like an extension to our family of another child for us.

"She always had a smile on her face.

"Everyone is pretty well shocked. Her mum and dad especially, her brothers and her husband. They are just very, very saddened."

Hyland said Racing Victoria and the VJA had been in contact with many participants to offer counselling and support.

"There is a lot of people with a heavy heart today in our community of jockeys, not just in Victoria but it stretches far and wide," he said.

"I guess all we can do is rally around people.

"Rally around all the participants that we are aware of that may be struggling and I'd just urge them to certainly contact Racing Victoria, and contact our association and we'll offer whatever assistance we can."

Officials called off Friday's Pakenham race meeting after the incident.

"In consultation this morning between Racing Victoria and the VJA it was determined that the best thing for the day was to not race at Pakenham. Give the industry a bit of a chance to take a breath and absorb what had happened," RV chief executive Giles Thompson said.

"We will be resuming racing tomorrow.

"It gives the industry a chance to come together, the community to come together.

"And also we'll be providing any support participants need at the tracks tomorrow and ensure we get through the day tomorrow as best we can."

Australian Associated Press