Motorcyclist using SA hills as racetrack

Motorcyclists are using areas of the Adelaide Hills as a weekend racetrack, police say.

Police have launched an operation that will target speeding motorists in the hills until April next year.

Over the past week, the number of motorcyclists caught speeding is double the rate of other road users.

Superintendent Anthony Fioravanti says on one stretch of road, seven motorcyclists were caught at more than 30km/h above the speed limit.

"We make no apologies for continuing with enforcement tactics along these high-risk roads until every motorcyclist realises the roads are not their racetrack," he said.