The aircraft climbed to Flight Level (FL) 120 without an airways clearance. A clearance had been requested by the pilot. Phraseology used by ATS was misinterpreted by the pilot as a clearance to climb to FL120. The Flight Service Officer (FSO) coordinating the clearance for VH-CSV failed to immediately recognise that the aircraft would enter controlled airspace when climbing above 10000 feet. The FSO was recently rerated in the position and lacked recent experience. The airspace divisions marked on the FSO's map were difficult to read. Phraseology used by the FSO was misleading. Significant Factors The following factors were considered relevant to the development of the incident: 1. The FSO lacked recent experience. 2. The FSO's work station map was difficult to read. 3. The FSO did not immediately realise that the aircraft would enter controlled airspace. 4. Phraseology used by the FSO was misleading to the pilot.