The pilot was relatively inexperienced on the aircraft type and bush flying. She had flown into Lamboo Homestead airstrip during the morning to drop off her employer. She had then flown over to the newly graded strip at Old Lamboo where her employer's mustering team was camped. After approximately one hour on the ground, the pilot decided to do a circuit of the airfield with one of the mustering team as a passenger. She had not landed at this airfield before and did not consult the aircraft performance charts. The performance charts indicated that twenty degrees of flap was required and that the available take-off distance required to clear the obstacles at the threshold was marginal. The pilot elected to make a flapless take-off. When approximately 2/3 along the 700 metre strip, and the aircraft did not appear to be accelerating normally, the take-off was abandoned. The pilot expected that the aircraft would stop within the remaining distance, however, the aircraft did not stop as expected and continued beyond the end of the strip. The aircraft was substantially damaged before coming to rest approximately 110 metres past the prepared threshold. Subsequent investigation indicated that the pitot tube was partially blocked and this had caused the airspeed indicator to under read.