Air traffic control (ATC) cleared the pilot of VH-EWF to descend to 5,000 ft and to divert left of the 144 VOR radial as required to avoid weather. However, the pilot subsequently diverted to the right of the 144 radial. A breakdown in separation standards occurred with VH-XFT, a scheduled passenger flight outbound from Rockhampton, on climb to 7,000 ft and tracking via the 116 VOR radial. The pilot of VH-EWF had requested clearance to track 5 NM left of the 144 radial. He was advised by ATC that the clearest conditions were to the west of that radial. The pilot later advised that he had diverted 5 NM left (west) of track. However, he had subsequently diverted to the right of the 144 VOR radial, and at 15 NM from the aerodrome, the aircraft was established on the 125 VOR radial.