Victoria Police say a family has sighted a boy matching the description of missing child Luke Shambrook, who was last seen on Friday near Lake Eildon.

Reports say the family was driving near Devils River when they saw a boy that looked like the 11-year-old who has autism.

Police have concerns for the welfare of Luke who wandered off from the Candlebark campground about 9:30am (AEDT) Friday.

• Ex-Labor ‘foreign fighter’ not charged
• Bleach could be making kids sick
• Web tricks us to think we’re smart

Police, SES volunteers and campers spent Friday scouring bushland Fraser National Park near Lake Eildon, before returning Sunday with the air wing, water police and the dog squad all assisting.

Marysville Police Sergeant Greg Paul said Luke may not even know that he is considered lost.

“This is the problem; unfortunately Luke, with the autistic condition, he might not respond to searchers, he may not even know that he’s lost,” he said.

“He won’t necessarily respond to his name being called, but that might change a little bit as he gets hungry maybe.

“We honestly don’t know what his status is, whether he’s curled up sleeping somewhere, or hiding or whether he would necessarily respond to us looking for him.”

Sergeant Paul said while search area was several kilometres wide, it was primarily focused on the area where Luke was last seen.

“We are concerned for his welfare – it is next to a lake, we’re not knocking any possibility out at this stage,” Sergeant Paul said.

He said emergency services resources were being thrown into the search from around the state, as well as dozens and dozens of campers.

“We’ve got a lot of searchers in the bush, we’ve got a lot of searchers searching in between the tracks – in the gullies and the spurs – we’ve also got people walking the bank of the lake, with the possibility that he might have fallen in the lake,” he said.

“We’ve also got boats in the water and we have people in suits snorkelling certain areas.”

Conditions favourable to Luke, police say

While the thick and varied terrain was difficult for the search party, conditions were favourable for Luke, Sgt Paul said.

Police said “dozens and dozens” of volunteers have joined the search. Photo: AAP

“The day-time temperature up here’s been fairly warm, overnight was cold, but not life-threatening cold, so that’s a good sign,” he said.

“Obviously he’d be hungry and cold by now … but survivability is quite high in these temperatures overnight.”

Sgt Paul said Luke’s family was distraught and worried.

“The extended family of Luke Shambrook are very grateful for the diligent and huge efforts put in by all emergency service units, volunteers, family and friends in searching for Luke,” the family said in the statement read by Sgt Paul.

“Our thanks to everyone for their ongoing prayers and support.”

Police said the boy was last seen wearing a jacket and he had a beanie with him.