Her partner, trainer Garry Kirkup, was behind the wheel and critically injured in the crash when their vehicle hit a tree.

Emergency services responded to the crash scene, on the Gundagai Road at Eurongilly, around 2.30pm on Sunday.

Kirkup, 54, was later airlifted to Canberra Hospital and has since  undergone surgery for what Canberra Racing Club chief executive Peter Stubbs described as "severe abdominal injuries".

Johnson, 25, rode trackwork in Canberra, and rode race meetings on the picnic circuit. Her last win came on October 7 when she rode Liabilityadjuster to victory in the Young Cup.

She last rode at Bong Bong on November 24.

Friends and members of the racing community have taken to social media to mourn the loss of their friend and colleague, with tributes flowing from trainers and jockeys.

“On behalf of everyone at the Canberra Racing Club, our deepest condolences to family and friends of Samara Johnson who has been tragically taken from us in a road accident,” Thoroughbred Park posted.

“A talented horse woman and friend to many.”

According to Racing NSW, Kirkup will undergo further surgery on Monday.

“Gary Kirkup’s son, Ben, has reported that his father remains in an induced coma at Canberra Hospital following yesterday’s motor vehicle accident near Junee,” the organisation said on its website.

“Ben said that Gary underwent abdominal surgery last night and has since undergone further CT scans this morning on his spine and brain, which he said have been cleared of injury.

“Gary has suffered abdominal injuries which will require further surgery today and has also suffered injuries to his hand and foot. Fortunately, Gary’s vital organs were not damaged.”

The organisation has also arranged counselling support for racing participants.

It is understood the pair was returning from visiting Ms Johnson's family in Coolamon when the car left the road and hit a tree head-on, with Mr Kirkup at the wheel.

The accident comes nine months after Canberra track work rider Riharna Thomson, who was close friends with Ms Johnson, died working at Thoroughbred Park.

Family and colleagues were able to visit Mr Kirkup in hospital on Sunday night and Canberra Racing boss Peter Stubbs said the industry was doing it tough after a horror 2017.

"It's been a tragic year for the club, Riharna and Samara were close friends and have mutual friends who still work in the industry, we're all devastated, it's been a really tough year," Mr Stubbs said.

"Samara was licensed as an approved rider who rode at picnic races and was highly successful at the picnics in this region and rode track work at Thoroughbred Park six days a week.

"She rode for Garry and freelanced for a number of different trainers on course, we're providing counselling support through our racing chaplain Bob Prior, while the other trainers have rallied to look after Garry's horses, he has about a dozen in his stables."

Ms Johnson was a rising jockey at the picnics and had ridden 26 winners in the past two years, which included the Tomingley Cup in April when she rode eight-year-old mare As Easy As to a seventh win in 10 starts.

Ms Johnson's final ride was in a trial at Canberra last Friday aboard Mr Kirkup's On the Catwalk and her most recent winner was on Liabilityadjuster at the Young Cup on October 7.

Mr Kirkup won the past two Camerena Sprints at Canberra's biggest race event of the year, the Black Opal Stakes day, with champion eight-year-old Highly Geared.

The mare raced on Oaks Day at Flemington during the Melbourne Spring Carnival last month and has made Mr Kirkup more than $300,000 since he bought her as an untrained four-year-old for just $12,000.

"Garry has had two stints training in Canberra, he first trained in the '90s for media personality Mike Willesee and then came here for a decade, before having a stint on the Gold Coast and then returning to Canberra four years ago," Mr Stubbs said.

"He's certainly a well-known trainer, not only in Canberra but around the Riverina area and Wagga and Cootamundra, we're all hoping for a speedy recovery for Garry."