A picture from the scene.
Diamond Creek locals have been left shaken and distressed after discovering the head of a decapitated kangaroo cooking on a public barbecue on Australia Day.
In a shocking case of animal cruelty, a skinned rabbit and the kangaroo's body were also located nearby.
Police were called to the picnic area of a park at the Diamond Creek Walking Trail around 8.20am on Wednesday.
3AW caller Michael told Neil Mitchell he'd been jogging on a nearby track when he noticed police on the scene.
"There were a lot of families here," he said from the scene.
Another woman rang to inform 3AW Mornings of what was happening, but was too upset to go on air.
Police are investigating and have made a plea to anyone who used the track from Tuesday evening onwards to let them know if they saw the dead animals.
Anyone with any information about the incident is urged to contact Crime Stoppers on 1300 333 000 or lodge a confidential report to www.crimestoppersvic.com.au.