Authorities have been dealt another blow during the renewed search for missing boy Gus Lamont at an outback property in South Australia.

In a surprise move, police and the ADF resumed efforts to find the four-year-old on Monday after last week signalling the operation had been changed to a recovery rather than a rescue and would be scaled back to an ongoing investigation.

South Australia Police Commissioner Grant Stevens announced a new taskforce had been formed to try and give Gus’ family some closure by expanding the search area in the hope of finding his body.

But the massive build-up of resources camped in and around the homestead where Gus disappeared is set to be frustrated with extreme heat conditions expected for the location, 43km outside of Yunta.

SA police confirmed that the first day of the reinvigorated search for the missing boy concluded on Tuesday with no evidence being located, and that they may need to adjust their search times to ensure the safety of emergency personnel.

“The coordinated search has progressed in zones outside of the original search area and will continue on Wednesday. Extreme heat forecast for Thursday is expected to restrict searching to the cooler morning period,” a statement from the lead investigators said.

“Resources used today include 18 police officers, 82 ADF members and 33 vehicles and SES resources including seven members, a drone and two utility terrain vehicles.

“The search for Gus, who was last seen on Saturday 27 September, is being conducted as part of Task Force Horizon that was announced this morning by Police Commissioner Grant Stevens,” the update concluded.

The magnitude of the search and the worldwide attention the story has garnered has been one of the biggest in South Australia’s history.

Local community members and hardened investigators have banded together in the hope of a breakthrough after the child, who was last seen playing outside the Oak Park sheep station home, disappeared despite frantic efforts from his grandparents to find him.

“Our efforts are focused on comprehensively searching the property, and we’re endeavouring to recover Gus for his family,” Commissioner Stevens said on Monday.

“We’re still looking for Gus, that’s really important to the family, to us, and for everybody who’s been involved.

“The Australian Defence Force has been excellent and we’ve got 80 ADF personnel up on the property, being coordinated by field search controllers that are police officers with South Australia Police, really just making sure that we leave no stone unturned.”