Australian Formula One driver Mark Webber has been seriously injured in a road accident while competing in his charity adventure sport challenge in Tasmania.

Webber, who drives for Formula One’s Red Bull team, was cycling along a road near Port Arthur, on the Tasman peninsula, when he collided with a Nissan X-Trail car and was knocked off his bike on Saturday.

The 32-year-old was competing in his own charity event, the Mark Webber Pure Tasmania Challenge, a 250km event using mountain bikes, kayaks and trekking, when the accident happened, around 12.40pm (AEDT).

Event director Geoff Donohue said he could not confirm “speculative reports” that Webber had suffered multiple arm and leg fractures until doctors had had a chance to properly diagnose the sports star.

“It would appear he’s suffered a fractured leg but until doctors confirm the extent of Mark’s injuries, we won’t know for sure — it’s still early days,” Donohue told AAP.

“Mark’s in good spirits. Paramedics attached to the event attended to Mark very swiftly and he’s had really good treatment at the scene before being transferred to hospital.

“It was a really unfortunate accident.”

Donohue said it was far too early to say whether the accident would impact on Webber’s pre-season training for the 2009 Formula One racing season.

“That’s jumping ahead a bit. He would certainly have other ideas about that. Right now, it’s a wait and see situation,” Donohue said.

“If any positives come out of this, you’d fully expect him (Webber) to be ready and willing, not only for his pre-season requirements with Red Bull Racing but also for the Formula One season proper.”

A Tasmania Police spokesman said Fortesque Bay Road, on which the accident happened, was a public route but added he did not know if the section was cordoned off for the event.

“The event is raced in a few stages and this part where the accident happened was the cycling stage,” Sergeant Jon Ford told AAP.

“As a result of the collision, the rider Mark Webber suffered serious but non-life threatening injuries. He was attended at the scene by paramedics attached to the event before being airlifted to the Royal Hobart Hospital.”

The male driver of the Nissan X-trail escaped injury, he added.

Webber was competing on the penultimate day of the five-day challenge, which also includes abseiling and whitewater rafting.