During the landing roll the aircraft suddenly veered to the left. The pilot took corrective action but the nose gear collapsed and the nose section of the aircraft struck the strip surface. Although the strip was in regular use it was not being inspected. It was constructed on a dry lake-bed and the combination of no rain and regular use caused a soft patch to develop about 430 metres from the threshold. When the aircraft entered this area the nosewheel progressively turned left until it reached the stop. The sideload now imposed was too great and caused the noseleg bearing to fail.