Flexible functional forms are used to examine the characteristics of production technologies. The Fourier functional form is capable of approximating any function globally, with the specified expansion. Unfortunately the exact form of the expansion is not known. The regularity conditions are likely to be violated without the exact form of expansion. In this paper we use a Bayesian approach to impose regularity conditions locally on a Fourier flexible functional from using agricultural production data. Monotonicity, concavity, convexity and elasticities are compared.