Software development paradigms currently used within industry are based on established models of the software life-cycle. As technology has evolved and become more accessible, more flexible approaches to the development of software systems have been advocated. Several new models have evolved over recent years based on more powerful software engineering tools and more sophisticated development methodologies. A more responsive approach to the development of software systems should allow the integration of alternative development models to be achieved without requiring changes in the development management structure. The paper introduces meta-models that allow more flexible management of software systems development. A management technique (generalised activity networks) is also introduced that assists in achieving this aim.