Australian motor sport legend Peter Brock has died after his car hit a tree during a rally in Western Australia today.

Brock was competing on the second day of the Targa West Rally when his Daytona Coupe hit a tree near the small community of Gidgegannup, about 40 kilometres east of Perth.

Brock, 61, was killed and his co-driver Mick Hone was injured. Hone was later taken to Swan Districts Hospital where he was reported to be in a stable condition.

The Confederation of Australian Motorsport said the crash happened at about midday local time. No other cars are believed to have been involved.

The road had been closed to traffic and spectators and road rules had been suspended for the race.

WA police spokesman Graham Clifford said the Major Crash Unit from Perth was at the scene and was investigating the accident.

"We believe that a vehicle is approaching a sweeping bend and for whatever reason lost control, left the road and collided with a tree," he said.

He said it was unclear how fast the car was travelling when it crashed into the tree.

"At the time it was a speed section, so it would have been travelling fairly quickly at that location," he said.

Tributes

Reigning V8 Supercars champion Russell Ingall says the motor racing community had been shocked by the accident and said Brock was well-liked and respected by fellow drivers.

"I had a lot of battles with him on the racetrack and he was fair," he said.

"You could trust the bloke and that was the difference. I wish we could say it was like that now but unfortunately it's not. He was one driver when you were racing against him, you knew you could trust him.

"He was an icon in the car but it was watching him outside the car and [with] the public - just the time he used to have for everyone. I don't think he missed an autograph. If anyone wanted one he'd stay there all night to get it."

Brock's former Holden Racing team public relations manager Peter Weissel says he was absolutely devastated.

"The guy is just an icon, it is just a dreadful week for Australia when you think of Steve Irwin and now someone like Brock who you always thought was invincible," he said.

"When I was working with the team he had the odd fairly large crash and he always seemed to jump up there with a smile on the face and you could hear him place a quick quote for the media all the time."

V8 Supercars spokesman Tony Cochrane described Brock's death as a huge loss for the sport.

"We'll obviously regroup and think about something very special for Peter at Bathurst this year, because Bathurst and Peter Brock were joined at the hip," he said.

"It's like taking a very big chunk out of our sport and I can't even imagine being at the mountain without Peter."

The editor of Wheels magazine, Jed Bulmer, described Brock as a consummate driving professional who won many accolades, but would be best remembered for his mastery of the race circuit at Bathurst.

"The great Australian touring car race and a race which is regarded as one of the most difficult touring car races in the world, and Peter was the nine-times winner there at what is known these days as the Bathurst 1000," he said.

"He had a long and very successful career there."

The president of the Confederation of Australian Motor Sports, Colin Osborne, says the death is an immense loss to the sport.

Mr Osborne says Brock touched the public.

"I think Peter's loss to motor sport is enormous but his loss to the entire community is even bigger than that," he said.

"Peter was an iconic figure not just in motor sport values, but he was also a great contributor to a number of community fields and I think as a result there are a lot of people in Australia - whether they were involved in motor sport or not - who feel as though they had a real connection to Peter Brock."

Australian motor racing identity Bob Jane described Brock as an Australian icon and a genuine person who would be greatly missed.

"[i am in] complete shock - I can't believe it," he said.

"I don't think he's had a serious accident on the race track, I think it's taken a dreadful rally, on a dirt road [sic] and bloody trees, for him to to to die, which is just an absolute tragedy."

'Peter Perfect'

Known as 'Peter Perfect' and the 'King of the Mountain', Brock won the Bathurst 1000 nine times in the 1970s and 80s.

Brought up with three brothers on the northern fringes of Melbourne, Brock developed an early affection for fast cars.

In 1969 the Holden Dealer Team gave Brock his first break to drive at the Bathurst 1000 - he placed third.

He became the team's lead driver and won the 1979 race by a record six laps.

Brock retired from full-time racing in 1997 and established his own charity to help disadvantaged children, but returned to Bathurst to win the 24-hour race in 2003.