Police said Mr Barnes had an engagement on Tuesday morning he was expected back for.
The group was travelling in a white Toyota Landcruiser troop carrier with registration HC 2687.
The man is known to one of the boys, and the second boy is a friend of that boy.
Police said several air searches had been conducted, however the vehicle and people involved had not been located.
It is not known exactly where they were going, however it is believed they were intending to hunt in bushland near Halls Creek.
Concerns are held for their safety and welfare, as they had limited food and water supplies with them.