The pilot of VH-HMV had been advised by Sydney FS that there was no known IFR traffic for his descent. During descent between 3,000 ft and 2,500 ft AMSL the pilot saw a Piper Twin Comanchee aircraft pass head-on about 200 ft above, and 15 m left. The pilot of the descending aircraft made several radio transmissions to ascertain the registration of the other aircraft without success. The aircraft was later identified as VH-CVS when its pilot answered a third aircraft also inbound to Walgett.
The in-flight conditions were VMC with the visibility reduced in smoke haze.
The pilot of HMV had been monitoring the area and CTAF frequencies on two radios since before his descent. He had not heard any transmissions from the other aircraft.
The pilot of CVS later said that he had made the required CTAF transmissions but that he had not transmitted a departure message on the FS frequency because it was saturated with aircraft traffic employed in fighting the bush fires. He did not see the inbound aircraft.