Workflow systems have been widely recognised as a successful way of modelling business processes. However, workflows can only present how processes are performed and do not support possible improvements to business processes. This issue of workflow optimisation has received a lot of attention in the literature, but the support of temporal constraints in this area has received significantly less. Furthermore, the issues that come from the enterprise, such as actors performing tasks, resources that these tasks utilise, etc. have not been taken into account.