The 25-year-old South Australian man was reported missing to police at around 4:30pm after becoming separated from his travel partner.
It is believed that the pair were travelling in convoy along Woomanooka Road in Durham when both vehicles became bogged.
“They were walking to get help when the woman turned back and the pair became separated,” police said in a statement.
On Monday, Queensland Police launched a land and air search to find the man.
The search has involved the State Emergency Service (SES) with assistance from two local mustering helicopters.

“Police are in touch with the man’s family as search efforts continue.”
The Durham area is expected to reach around 40 degrees for most of the week.
