Family told investigators that Will could have travelled a long distance on foot as he was “energetic”, and could have wandered into a house near where he went missing, the spokeswoman said.
“We would expect that he would be able to travel a lot of distance … he is also not dressed for the elements of a cold evening,” Ms Newman said.
“He’s very food-focused, so it’s not unreasonable he would walk up to a house and let himself in if the door was unlocked. He could go inside, walk up to the fridge or cupboard to get something to eat, and then put himself to bed.
“We’re asking the public within the vincitnty to please check bedrooms or outhouses on their property, and if they do sight him, to call triple zero.”
The search includes Victoria Police’s Air Wing, the Search and Rescue Squad, the Dog Squad, local uniform members in 4WD’s and police on bikes.
The temperature at nearby Wallan is expected to reach zero degrees overnight, the Bureau of Meteorology says.
A spokesman for the State Emergency Service said members of the Whittlesea branch had arrived at the scene just after 5pm to help police with the search, with another crew from Craigieburn later joining the search.
Anyone who sees Will is urged to call triple zero (000).