Supply response equations were estimated for a number of regions in south-eastern Australia using the area sown to wheat as the response variable. These equations were used to determine the effect of delivery quotas on the area of wheat sown in those regions. Results from this study indicate that delivery quotas were only effective in reducing wheat plantings in the south-eastern Australian wheat-belt in the 1970-71 season. Plantings in other seasons in which delivery quotas were applied could be explained using variables such as wheat prices and a time trend.