Abstract: In recent decades, routing in Mobile ad hoc Sensor Network (MASNet) have become an active research area due to its impact in various science and engineering applications. The increased demand for energy has become a great concern in industrial market which in turn has led to the development of various energy efficient sensor networks. This research study mainly focuses on secure and energy efficient routing in MASNet. A secure multipath algorithm has been presented in this study which facilitates the nodes in MASNet to carry out on-demand discovery and forming set of paths while identifying a disjointness threshold, denoting the maximal number of nodes shared between any two paths in the set of the k established paths. The proposed Rectangular Zone based Location Specific Routing (RZLSR) approach is energy efficient, adaptive, secure and uses labels to carry the disjointness-threshold between nodes during the route discovery which improves the quality of services. The broadcasting scheme used in this approach is based on RECT which forms an efficient framework for routing data between source and destination. A set of security mechanisms, based on the use of Watchdog and digital signature, are used to protect the route discovery process. The simulation results indicate that the proposed approach provides significant performance with lesser overhead, energy efficient and better network lifetime.