The design of a manufacturing system requires modelling and performance evaluation techniques. To support this process, a modelling method based on Petri nets is proposed in this paper. A new class of coloured Petri nets is introduced, which is well suited to the modelling of manufacturing systems. Using this net class, the structure and the work plans of a manufacturing system can both be modelled separately. A library of model templates helps to create large models. The different model parts are merged automatically to create a complete model of the manufacturing system. Measures of interest can be obtained from the model by numerical analysis or simulation, showing its performance and dependability. The usefulness of the approach is shown by applying the proposed techniques to a real-life manufacturing system.