Christopher was last seen in Werribee on May 2.
Police have concerns for his welfare due to his age and the length of time he has been missing.
Christopher is Caucasian in appearance, 183cm tall with a thin build and has short brown hair.
He is known to frequent the Werribee, Hoppers Crossing and Geelong areas.
Police have released an image of Christopher in the hope someone recognises him and can provide information regarding his current whereabouts.
Anyone with information about Christopher’s whereabouts is asked to contact Werribee Police Station on 9742 9444.