An air and ground search for an autistic boy missing in dense bushland in Melbourne's outer east continued through the night without success.
William Wall, 14, left his Launching Place home about 7am on Tuesday to go for his daily walk in the Yarra Ranges.
He told his family he would be gone for 15 minutes but never returned.
William, who has high functioning autism, left home without his mobile phone and police are concerned for his welfare, but are heartened by the fact he knows the area well.
"Everyone is hoping at the moment that he will be ok," William's father, Shane Wall, said on Tuesday night.
"I want to get him home."
The air and ground search involving local police and the State Emergency Service will continue on Wednesday.
Searchers have concentrated on the Warburton Rail Trail, which runs about 40km from Lilydale to Warburton, which covers difficult terrain, and the O'Shannassy Aqueduct Trail above Warburton.
The teenager is described as 177cm tall, with a lean build, mousy brown hair and a lazy right eye.
His family said he was wearing a dark hooded jumper, dark-coloured track pants, black runners and had a CamelBak hydration backpack.
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