Heywood police described the vandalism as "disgusting and pointless".
POLICE are disgusted after vandals caused $4000 worth of damage to a picnic area in the Cobboboonee State Forest north of Portland.
It is believed the damage was caused some time between August 26 and September 2 in the Jackass Ferngully picnic area, police said.
Acting Sergeant Andrew Dunlop of Heywood police said the toilet block copped most of the damage, with hand rails, toilet roll holders, and wooden walls all destroyed.
A large visitor information display board was also damaged.
"It's a disgusting and pointless act," Acting Sergeant Dunlop said.
Crime scene officers have attended the scene.
Anyone with any information about the incident should contact Portland police on 55231999.