Potential effects of alleged monopsony pricing of farm food products by supermarkets on farm product prices, quantities, incomes and land values are assessed relative to competitive behaviour. A comparative static equilibrium model is used. For export products and the few import competing products, the effective food input supply curve facing the supermarkets is close to perfectly elastic and this limits monopsony behaviour. For the non-traded food products, the ease of reallocating the fixed supply of aggregate agricultural land between traded and non-traded food products means a highly elastic food supply function for non-traded food products, and very limited monopsony effects.