In this paper, a real world short-haul commodity routing problem is presented. This problem shares several similarities with vehicle routing problem with time windows (VRPTW) and the service network design problem (SNDP), but also has its own specific structures that do not exist in VRPTW or SNDP. A task based formulation is developed for this problem and a variable neighbourhood search metaheuristic approach is proposed, resulting in a visible improvement over the original routing plans according to experimental tests over three real-life instances. Apart from introducing a new real-world commodity routing problem, another main contribution of this paper is a task based formulation that allows commodity flows being considered as nodes in a routing network. Thus algorithms that were designed for VRPTW or SDVRP can also possibly be adapted to solve this commodity flow problem.