Police are appealing for public assistance to help locate missing youth Sienna Johnson.
The 11-year-old was last seen at Southern Cross train station on 10 May.
It is believed she caught the train from Castlemaine to Melbourne.
Police have concerns for her welfare due to her age.
Erin is about 130cm tall with a thin build, brown eyes and has blond fair hair.
Police have released an image of Sienna in the hope someone recognises her.
Anyone who sights Sienna or who knows of her whereabouts is urged to contact Castlemaine Police Station on 5470 4105.