Two Australians are out of the Tour de France after a number of high-profile riders tumbled during a dramatic third stage.

Sprinter Caleb Ewan must abandon the tour after smashing his collarbone on the road in a high-speed crash in slippery conditions at Pontivy.

The Sydneysider was in contention to win the third stage when he appeared to clip Tim Merlier’s wheel on the turn of the final sprint.

While falling to the road as his wheel seemed to slip out from under him, Ewan also brought down top rider Peter Sagan.

Merlier went on to win the stage and a recovered Sagan rode on, shaking his head, while Ewan lay on the ground in pain. He was treated by paramedics and a later x-ray confirmed he had a right collarbone fracture.

Crikey, that was bloody terrifying. Hopefully @CalebEwan and @petosagan are ok. #TDF2021 #pontivy pic.twitter.com/5uwppcCtZw

— Owen (@OSmithFFC) June 28, 2021

It is the end of the 26-year-old’s dream of winning a stage in all three grand tours this year after he had begun his campaign with two brilliant wins at the Giro d’Italia.

The narrow roads in the stage finale had taken a toll on many competitors who crashed as the peloton rode at full speed.

Another Australian, Jack Haig, was involved in a crash with a large group of riders just four kilometres from the start of the race. He was forced to pull out.

Last year’s runner-up, Primoz Roglic, went down about nine kilometres from the end.

Roglic immediately got back on his bike but lost ground to his main rivals as his Jumbo-Visma teammates tried to pace him back to the peloton.

Defending champion Tadej Pogacar was slowed a few kilometres further down the road following another crash but it was unclear whether he also tumbled.

Former Tour champion and Ineos-Grenadiers leader Geraint Thomas had also hit the tarmac. He suffered a dislocated shoulder but managed to get back on his bike.

Robert Gesink was also involved in that fall, 37km into the stage, and was forced to abandon.

With his racing kit lacerated, Thomas struggled at the back. Teammate Luke Rowe waited for him and the Welsh pair lagged two-and-a-half minutes behind the main pack.

With the help of more teammates they eventually caught the peloton after Thomas changed his bike.

Thomas was 20th overall before the start of the stage, 41 seconds behind race leader Mathieu van der Poel. He predicted “a stressful day” because of the bad weather conditions.

The race started in the rain in Lorient and a group of five riders surged ahead immediately.

Behind, the peloton rode at a pedestrian pace and riders were accompanied by scattered showers making the roads slippery and dangerous.

Riders have since taken to social media to express concern about the design of the route.

The professional cyclists union said it was in “direct conversation with riders” after a “crash-marred race”.

-with AAP