The role of clusters and clustering in economic development is of current policy interest, in part because of analyses and studies that have associated these forms of collaboration with regional and local prosperity and development. Although some of the literature supports or starts from this association, there are also critiques of the clusters concept and its feasibility as a policy development and intervention strategy. Intrinsic to part of these concerns has been a view that clusters cannot be created without business involvement and input at the heart of the process. The paper addresses this issue via an examination of four cases of potential clusters development from the perspectives of the businesses involved. Although clear evidence for the existence of a cluster could only be established definitively in one of the four cases, there were extensive indications of clustering as a collaborative activity across all four cases. Based on this, a process of clusters formation and emergence was developed that applied to the cases. This process consists of several phases of clusters emergence and points to three stages of clusters development: potential, emerging, and established. A key implication is that processes of clusters formation may provide an opportunity for the formulation of 'bottom-up', contextually sensitive clusters development strategies for groups of businesses.