Aussies are being warned to avoid AI search engines after incorrect theories about a four-year-old boy who went missing in the outback spread on social media.

August 'Gus' Lamont was last seen playing in a mound of dirt near his grandparents' homestead on a sheep station 40km south of Yunta, in eastern South Australia, at about 5pm on Saturday, September 27.

He had vanished by the time his grandmother went to call him in, some 30 minutes later.

Police began searching the 60,000ha property shortly after Gus disappeared but found no sign of the little boy.

An extensive land and air search was launched, with hundreds of people scouring the surrounding area in the intervening days, including police, SES volunteers, and members of the Australian Defence Force.