'It would be uncomfortable for him': Police search dams for four-year-old boy missing from remote homestead

Crews will continue to search into the night for a four-year-old boy who went missing on his remote homestead about 235km north-east of Adelaide over the weekend.

August, or Gus, was last seen on a property in mid-north South Australia, about 40km south of Yunta, at 5pm on Saturday.

He was reportedly playing in his grandparents sandpit at this outback homestead.

READ MORE: Thousands hit with another Optus outage on weekend

Local officers searched the area with a helicopter and an infra-red camera that same night, but were unable to find him.

Crews have used trail bikes, ATVs, horses and a drone and a helicopter to scour a 2.5km radius from where Gus was last seen.

Today, police attached to water operations searched dams and tanks on the property while officers on horses searched the property.

"As you can see from the enormity of the property here it's expansive. That's why we've put as many resources as we can into finding young Gus," Superintendent Mark Syrus said.

"This poor lad just four years old and very close to the family so they're devastated."

Gus is described as Caucasian with long, blonde, curly hair.

BREAKING: Two people found dead at Brisbane home

He was wearing a grey sun hat, a cobalt blue t-shirt with a yellow minion from the movie Despicable Me on the front, light grey long pants and boots.

His family have declined to release an image of him.

It is believed to have gotten down to six degrees in the two nights he has been missing

"It would be uncomfortable for him but don't anticipate those sub-zero temperatures which is quite common up here," Syrus said.

Anyone who sees a boy matching his description or has information is urged to contact Crime Stoppers.

DOWNLOAD THE 9NEWS APP: Stay across all the latest in breaking news, sport, politics and the weather via our news app and get notifications sent straight to your smartphone. Available on the Apple App Store and Google Play.