University of Wollongong GIS-based Landslide Inventory has been expanded to facilitate reliable modeling of landslide susceptibility and hazard zonation over the wider Sydney Basin area. Landslide inventory development is underway after designing a state of the art inventory structure following a comprehensive international literature review. The alphanumerical as well as spatial data bases of landslides have been updated after field verification of landslides in Sydney and Newcastle as the stepping stone for the wider Sydney Basin area landslide susceptibility model development. In the lead up to this, landslide susceptibility modeling in two smaller sub-regions of Sydney (Wollongong Local Government Area and the Picton area) has been undertaken by the Landslide Research Team at the University of Wollongong. In tandem with the development of the landslide inventory, new tools and methods have been developed to aid application of Data Mining techniques within a GIS framework to obtain more reliable modeling, analysis and synthesis. The main aim of this paper is to report the latest advances in landslide inventory development, preparation and compilation of data for the modeling work.