This paper describes a dynamic microsimulation model of cohort demographics that has been developed to consider the working lifetime in Australia. The model provides a valuable resource for studying dynamics in Australia since, in addition to the usual advantages of microsimulation analysis, Australian panel data is scarce. The model possess a highly flexible structure. Specifically, the modular framework of the model permits the addition or omission of cohort characteristics as desired, and the use of transition probability functions facilitates transparent sensitivity analysis.