The mutilated body of the eastern grey kangaroo was discovered on Winter Street in Ballarat during a routine street clean on August 1.

Its legs appeared to be tied together with an orange rope.

Ballarat City's animal management team alerted the Department of Environment, Land, Water and Planning and the state's Conservation Regulator, which is now investigating.

The animal died about 12 to 24 hours before it was found, with its exact cause of death considered "unknown".

The regulator urged anyone with information to contact Crime Stoppers.

"Kangaroos, like all wildlife, are protected in Victoria and actions of cruelty towards them are unacceptable and illegal," Grampians manager of regulatory operations Brian Hamer said.

"We take all allegations of wildlife crime seriously and we are investigating how and why this kangaroo died."

Under Victoria's Wildlife Act, it is it illegal to hunt, take, destroy, injure or interfere with wildlife in the state.

If caught and found guilty, those responsible could face up to two years in jail and or a $92,460 fine for aggravated animal cruelty.

Australian Associated Press