The pilot had landed at the one-way agricultural strip in order to deliver covers for a load of superphosphate. The subsequent take-off was normal until the point where the tail of the aircraft was raised. At this time the aircraft was affected by a strong wind gust, and the pilot was unable to maintain directional control. The aircraft ran off the side of the strip and struck scrub and a steel fence post. The wind at the time was relatively strong, giving a substantial downwind/crosswind component. Although the pilot had operated from this strip on numerous occasions, he had not worked from it for about 12 months. The strip posed difficulties because it changed direction to the right over the crest of a hill. Due to a strong left tailwind, the pilot had to maximise the take-off run available. The path chosen, combined with the prevailing wind, took the aircraft off the right side of the strip before it had attained flying speed.