Increasing global parcel shipping volumes and just-in-time delivery force distribution centers to handle increasingly larger volumes of greatly varying parcel types. Automated material handling systems are essential to achieve these challenging requirements. A push divert sorter is one of these systems. This system uses a series of sliding plastic blocks to divert items from a main conveyor onto specific lanes. The performance of a push divert sorter is highly influenced by the design of components interacting with parcels. The shape and materials of these components influence the locations, directions and magnitude of forces acting on parcels, which influences their dynamic behaviour. The influence of the design of these components on the system performance is analyzed in the study. Moreover, based on these insights, an improved design is proposed and assessed.