Treadmills have been branded a potential health hazard after dozens of children suffered burns or crush injuries on the whizzing running belts.

NSW Fair Trading issued a safety warning about the machines on Wednesday and said about 40 people are hospitalised in the state every year because of treadmill-related accidents.

It pointed to a recent survey by the NSW Agency for Clinical Innovation (ACI) which showed that in the past two years 74 people in NSW have suffered burns on treadmills.

Three of those were adults and the rest children with an average age of three and a half.

The ACI survey showed an increase in accidents after October 2012, with eight patients presenting at the burns unit of the Children's Hospital at Westmead, in Sydney's west.

Five patients needed surgery, including skin grafts and one will require long-term scar management.

Associate Professor John Harvey, head of the Children's Hospital at Westmead's burns unit, said he most frequently sees treadmill injuries among toddlers.

"These include crush injuries to the hands and fingers, fractures and most commonly serious friction burns to the hands and fingers," he added.

NSW Fair Trading urged parents to keep youngsters well away from treadmills.