Outback search to resume for missing four-year-old boy

A search for a missing four-year-old boy will resume at an outback sheep station more than two weeks after the child disappeared.

Gus Lamont went missing at the Oak Park Station homestead, about 40km south of Yunta, in South Australia's Mid North region, on September 27.

The "shy, adventurous" pre-schooler's grandmother last saw him playing on a mound of dirt at 5pm.

He was nowhere to be found when she returned 30 minutes later.

SA Police have pledged to "never give up hope of finding Gus", with the search to resume on Tuesday.

Police and army personnel will look at a section of the farm not covered by the extensive search to date.

"The search ...will concentrate on an expanded area outside of the zone already searched extensively following Gus's disappearance," a police statement said.

"There continues to be regular and close engagement with the Lamont family who are continuing to assist with the investigation."

A police helicopter and a tracker last week conducted a significant search at a dam about 3.5km west of the homestead after a small boot print was found.

The print was subsequently found not to be related to the four-year-old, police said.

A special drone with infrared capabilities was used for an aerial search of the property in the preceding days.

Results of the drone analysis will be finalised in the coming weeks.

Police scaled back the search after hundreds of police, defence personnel and volunteers scoured the property for almost a week.

Police are continuing to investigate the boy's disappearance, including the possibility he might not have become lost while playing outside the property.

The investigation is being managed by Missing Persons, part of the Major Crime Investigation Branch.

However, senior police had spoken to Gus's family and told them he was unlikely to still be alive, based on expert advice about the outback weather conditions and clothing he was wearing when he disappeared.

Gus has long, blond, curly hair and was last seen wearing a grey sun hat, a blue T-shirt with a yellow minion on the front, light-grey long pants and boots.