VH-SMH was on a positioning flight from Camden to Sydney at the conclusion of an instrument rating flight check. The aircraft was instructed to contact Sydney Approach on departure for airways clearance into controlled airspace but was subsequently observed on radar tracking towards Sydney, approximately one mile north of the 062 localiser, climbing through 3000 feet. VH-SMH continued to track parallel to the localiser, reaching 4200 feet by 18 miles from Sydney before contact was established with Sydney Approach. Conflicting traffic was VH-TJN, also inbound to Sydney on the 062 localiser, on descent to 3000 feet. VH-TJN was passing 5000 feet, and was about 2 miles ahead of VH-SMH, as it reached 4200 feet. The pilot of VH-SMH later said that, as with other departures from Camden that day, he had called Camden Ground prior to engine start to advise that he would be taxiing shortly, and requested airways clearance. He did not recall what altitude this flight was planned at, but said that he would have set 4000 feet on the assigned altitude indicator as this was the lower limit of controlled airspace overhead Camden. Once airborne from runway 26 a simulated engine failure was initiated by the check pilot. Recovery time was minimal and Camden Tower advised the pilot to call 123.4 (Sydney Approach) for airways clearance. This was accomplished but the pilot said he could not now recall the actual clearance instructions. The controller then asked the pilot if Camden Tower had asked him to call Sydney Approach for a clearance, and did the pilot recall what Camden Tower had said. The pilot advised that Camden Tower had told him to expect clearance at 4000 feet and to call Approach. Air Traffic Control were expecting VH-SMH to call Sydney Approach and had planned to hold the aircraft for traffic sequencing.