Mark Webber has sustained serious injuries while competing in his outdoor adventure race in Tasmania.

The Australian, who drives in formula one for Red Bull, is believed to have collided with an oncoming four-wheel drive car on an open road near Port Arthur, in the south east of the island state, as he was riding a mountain bike on Saturday.

"As a result of the collision, (Webber) suffered serious but non-life threatening injuries," a police spokesman said.

"He was attended at the scene by paramedics attached to the event before being airlifted to the Royal Hobart Hospital."

Some reports, backed by a source with the Tasmanian Ambulance Service, suggest the 31-year-old suffered multiple arm and leg fractures.

"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," said event director Geoff Donohue.

Source: GMM