Organisers of the Indian Pacific Wheel Race have cancelled the cross-country cycling race after a rider was killed in a collision with a motor vehicle just south of Canberra.
A male competitor in the inaugural race, which started in Fremantle, WA and was heading to Sydney, was killed on the Monaro Highway at about 6.25am Friday.
He was pronounced dead at the scene, ACT police said.
Police said the driver of the vehicle involved was in shock and being treated at hospital. They noted alcohol and speeding had been ruled out as factors in the collision.
Race organisers said they were working with authorities to investigate the "tragic incident" and that they intended do their own detailed investigation.
On Friday afternoon they had confirmed the race had been cancelled "with immediate effect".
"Every effort is being made to personally get in contact with riders that remain on the road to inform them of the situation," the IPWR organisers said in a statement.
"This is a difficult time for everyone involved, along with their families, and their well-being is our primary concern."
Organisers and police have not confirmed the identity of the rider involved, saying his next-of-kin had not yet been notified.
Competitor Stuart Edwards wrote on Facebook that he would be pulling out of the race after he received news of the death.
"I've decided I won't play with the cars any longer, my days of riding long distance on roads are over I reckon," Mr Edwards wrote before the official cancellation.
"I'm sitting by the side of the road in tears."
Police said passers-by had come across the crash and stopped to help but were unable to save the cyclist.
"[The driver] will be spoken to later by our Crash Investigation Reconstruction Team," Sergeant Meagher said.
"It [was] early in the morning, it [was] dark; there was no fog at the time."
"I can suggest given the nature of the collision an investigation into the circumstances would suggest the rider of the push bike died at the scene."
The Monaro Highway was closed with traffic diversions in place for over five hours after the crash, but has since reopened.
Sergeant Meagher praised the bystanders who stopped to help, and implored people to drive safely and be aware of vulnerable road users.
The death was not the first incident to mar the race, on Monday morning, Irish participant Eoin Marshall was hospitalised after a collision with a car in Tarlee, South Australia.
Mr Marshall was treated for a head wound and transferred to hospital for surgery. His Instagram shows pictures of stitches being applied to the back of his head and a skin flap being lifted to show skull underneath.
"We all wish Eoin a speedy recovery," an IPWR statement said at the time.