It's motorsport but not as you know it - the humble ride-on lawn mower is being turned into a speed machine in this quirky and sometimes hilarious form of racing.

Nowra's Gary Eccles says he's raced almost everything on wheels, but nothing gives him a thrill like climbing on board his modified lawn mower and putting the old slasher at full throttle.

"It's absolutely amazing, the adrenaline rush is crazy and you can't beat it," he says.

"Lawn mower racing gets all types, there are people that like V8s, there's people that like anything, but what brings them together is the hands-on passion for building something and racing something."

Gary's a member of the Shoalhaven-based Showmow Racing Australia - a group of lawn mower racing enthusiasts who not only hold competitions, but travel around country shows in New South Wales putting on demonstrations.

"The reaction we get is really good, the showground's empty when we go on and within five minutes it's full - once people hear the rumble of the lawn mowers they come running from all over the place," Showmow Racing president Greg Lynch says.

The group started in Nowra in 2004 with four mowers and now has about 40 competitors, as well as branches in other cities in NSW.