Flood is one of the major natural disasters in Australia. Spatially refined understanding of the impacts of floods in monetary terms can help us to reduce flood damages, losses and costs through improved spatial targeting and implementation of relevant mitigation measures. The increasing availability of high resolution spatial data and GIS-based capacity for spatial data manipulation are enabling more efficient and accurate economic estimation of flood damage at finer spatial resolution. Different techniques and procedures for economic assessment of flood impacts have been deployed in many major emergency management and insurance organizations around the world, but none of them are designed for producing accurate economic flood damage estimation at fine spatial resolution. In this paper, our efforts in developing a GIS-based approach to spatially refined characterisation of flood impacts and some case study results are presented, including DEM-based modelling of flood water depth, collection and organisation of detailed building inventory data, adaptation of a set of stage-damage curves, and economic assessment of flood damage at property level for a case study area in Melbourne.