Police have scaled back their search for four-year-old Gus, who went missing six days ago from his family’s remote homestead in South Australia.

Gus — described as an adventurous and shy child and a good walker — is believed to have wandered from the property, which is about 40km south of Yunta, about 5pm on Saturday.

An extensive search has been ongoing after his family were unable to find him and has grown more desperate each day.

Today, Assistant Commissioner Ian Parrott announced that police would scale back what he described as “one of the largest, most intensive searches” for a missing person in the state in recent times.

He said police were working with a lack of evidence, after only finding a footprint earlier this week, and received expert advice that Gus is unlikely to have survived.

“We’re confident that we have done absolutely everything we can to locate Gus within the search area, but despite our best efforts, we have not been able to locate him,” he told reporters.

“Unfortunately, we are now having to scale back this search for Gus.”

At least 50 people had been on site every day of the search and scoured through 25km of tough terrain around where Gus was last seen.

Emergency crews will no longer be searching the property, and defence personnel who were assisting will be stood down.

Police will continue their investigation and follow any lines of inquiry.

They do not suspect foul play.

“We will not rest until we can find the answer to why Gus has gone missing and, hopefully, for the family, return him to them,” Parrott said. 

Parrott said police had spoken to his heartbroken family on Tuesday to prepare them for the possibility that Gus may not be found alive.

“Life’s not supposed to work where a parent loses a child, it’s supposed to work the other way around,” he said.

“I think it becomes incredibly traumatic and upsetting for families who lose children, and particularly in circumstances where you don’t necessarily know the answers.

“The family are really upset by this, as you’d expect.”

Earlier this week, Gus’ family said they were “devastated” and “deeply distressed” by his disappearance.

“This has come as a shock to our family and friends, and we are struggling to comprehend what has happened,” they said in a statement.

“Gus’ absence is felt in all of us, and we miss him more than words can express.

“Our hearts are aching, and we are holding onto hope that he will be found and returned to us safely.”

Parrott said the officers involved in the search were also devastated by the “tragic” and “very, very sad” situation and outcome.

“The people involved in this search are parents, family members, often with young siblings or young ones around, so we all feel the pain and the heartache that’s associated with a young child going missing,” he said.