Beanie the biggest clue in search for missing Victorian boy

The beanie found in the search for autistic boy Luke Shambrook shows he headed away from water in the Victorian national park where he went missing, renewing hopes he will be found alive.

Police do not know when Luke, 11, dropped the beanie that was found on Monday evening.

It could have been lying there since Good Friday, when he was last seen in Lake Eildon National Park.

Police, the SES and volunteers are doing line searches near the area at Devil's Cove, Acting Senior Sergeant Andrew Walker says.

"We're happy that we've found a piece of clothing belonging to Luke and it indicates that he has walked away from the water," he told reporters on Tuesday.

The terrain is slippery and rain is hampering the search, but there is no plan to scale back resources.

"We're still treating this as a search and rescue operation," Sen Sgt Walker said.