Agent based models have gained wide acceptability in transport planning, however, the modelling frameworks have been facing a practical dilemma: demand and supply sides are not fully integrated with each other. So to overcome this problem, time-dependent origin and destination (OD) matrices are traditionally used to integrate sophisticated agent based demand (Activity-based models) and supply (Dynamic Traffic Assignment) models, which doesn’t allow exploitation of several advantages offered by these rich frameworks. Earlier integration efforts exist, such as TRANSIMS and MATSim, however these are still based on various simplifications. This paper reports development of the SimMobility mid-term simulator, which is an agent based, fully econometric, activity-based demand model, integrated with a dynamic traffic assignment model. This SimMobility mid-term is part of a much larger simulation platform that also contain long term and short term models. The SimMobility mid-term architecture comprises three interconnecting components, namely the pre-day, within-day and supply simulators. Models within these simulators are developed utilizing the various datasets from Singapore. The paper also presents some preliminary results obtained from the current implementation to provide an idea about its efficiency in terms of computational time and predictions accuracy. Avenues of future work are also mentioned to improve the capabilities of the modelling framework.