Waikaraka Park Speedway: Photographer hit by car a 'freak accident'.

Businessman and part-time photographer John Sprague.

Waikaraka Park Speedway president Frank Irvine says last night's incident where a photographer was hit be a stock car is a "freak accident".

"From what I understand, a gear box blew up and parts of it got stuck on the brake panel causing the vehicle to veer off the track," Irvine said.

"The photographer was standing where he should be, but the out-of-control vehicle must have got him in the back."

John Sprague, 58, has lost a lot of blood and remains in critical condition at Auckland Hospital, according to a close friend.

Irvine said the man was an "experienced" photographer and has been shooting at the speedway for "a long time".

"He's got plenty of experience and knows what he's doing, but how do you stop accidents from happening," Irvine said.

"At the end of the day, this is a freak accident."

Irvine said police were investigating, and the Speedway would leave it to the police to determine the outcome of what actually happened.

Colin Koh, 58, a close friend of Sprague said he was shocked when he learned of the accident.

"We've been friends for many years and I am absolutely shocked," Koh said.

"I've spoken to his daughter, and our thoughts and prayers are with him and the family."

Koh said the Henderson businessman has a passion for photography and started shooting at speedways about 10 years ago.

"John's a businessman in the magazine cover lamination industry, but he's also a hobby photographer with a love for speedway cars," Koh said.

Sprague has three adult children including a daughter who is a senior nurse, Koh said.

"All we know at this stage are what's been reported in the media," he said.

"But there's a lot of questions on what happened and why was he allowed to be in a position where the car could hit him."

Worksafe says it has been notified of the incident.

"WorkSafe will make preliminary enquiries," a spokeswoman said this morning.

St John Ambulance were told of the incident by paramedics already at the speedway just before 8pm last night.

The man was taken to Auckland Hospital in a critical condition.

Police said in a statement that a worker at the speedway had been hit by a stock car, sustaining critical injuries.

A man in the crowd, who did not want to be identified, told the Herald the photographer was in the infield area when he was struck by a stock car being driven by a longtime Waikaraka driver.

"The car came around the back straight and around the turn. The person standing there was obviously too close to the track and the car clipped him.

"He flew 10 metres and rolly-pollied and then stayed still ... the car was going full speed."

As others rushed to help, the driver emerged from his car, the man said.

"He put his hands on his head."