We present a modular workflow platform for the simulation and analysis of natural hazards. The system is based on the CSIRO Workspace architecture, allowing transparent data interoperability between input, simulation and analysis components. The system is currently in use for flooding and inundation modelling, as well as research into bushfire propagation. The modularity of the architecture allows tools from multiple development groups to be easily combined into complex workflows for any given scenario. Examples of platform usage are demonstrated for saline intrusion into an environmentally sensitive area and image analysis inputs into a fire propagation model.