The death of a "much-loved" jockey in Darwin has sent ripples through the racing community, just a day after another female rider died in Victoria.

Melanie Tyndall, 32, who is also a police officer, had been riding at Fannie Bay when her horse fell during the third race and she later died in hospital on Saturday night.

Thoroughbred Racing NT and the Darwin Turf Club confirmed Tyndall's death in a joint statement on Saturday night.

"Melanie's mount Restless appeared to clip the heels of another runner, she became unbalanced and was dislodged near the 300-metre mark," the statement said.

Tyndall was treated at the scene, taken to the Royal Darwin Hospital and later died.

"Melanie was a much-respected member of the Northern Territory racing family and her sad passing will be felt by many within the industry," TRNT chief executive Andrew O'Toole said.

Acting NT Police Commissioner Michael Murphy said Ms Tyndall, a constable, had also been a respected member of Casuarina Police Station.

Mr Murphy said he had personally assured her partner and her father that the police family stood ready to help in whatever way they could.

"This is an incredibly difficult time for her partner, family, friends, colleagues and the wider police family," he said in a statement.

"Melanie had forged deep and strong ties in our small community and police are providing every possible support to her family."

Darwin Turf Club chairman Brett Dixon said the jockey's death was deeply saddening, before sharing condolences to her family and friends.

The tributes continued with Australian Jockeys Association chairman Des O'Keeffe telling AAP it was shattering to learn of the death of the Northern Territory jockey.

"Mel was a much-loved and highly-respected and successful jockey who had achieved great things in her professional career and outside the world of horse racing," he said.

"The thoughts of all Australian riders are with her family and her Northern Territory colleagues at this time."

Trainer Michael Hickmott paid tribute to a "remarkable human being".

"If people only knew the hurdles you conquered in your life to make what you did of yourself," he tweeted.

"We were all so proud of what you achieved. You defied the odds."

Tyndall's death comes just a day after apprentice jockey Mikaela Claridge died from injuries suffered in a trackwork accident in Victoria.

South Australian jockey Eran Boyd tweeted she felt numb.

"It's so hard to comprehend losing another friend & fellow rider. These past 2 days have absolutely shook our industry. Heaven has gained another angel."

Libby Hopwood, who retired after suffering brain injuries in a fall in which a rider was killed, tweeted: "Simply lost for words. Sometimes the price of this industry seems too high."

In 2013, jockey Simone Montgomerie died on Darwin Cup day after falling from a horse.

TRNT and the Darwin Turf Club will hold a media conference on Sunday afternoon.