In this paper, we use a new class of generalized convex n-set functions, called (F,rho, sigma, theta)-V-Type-I and related non-convex functions to establish appropriate duality theorems for three parametric and three semi-parametric dual models to the primal problem. This work extends an earlier work of Zalmai [Computer and Mathematics with Applications 43 (2002) 1489-1520] to a wider class of functions.