The thermal behaviour of rocks has recently become an important topic for rock engineering due to developments in deep underground applications. Because of the extensive depth of these applications, more hazards occur such as rock bursts, external fires and gas explosions. The main reasons behind these underground rock disasters are the high temperatures and pressures. Therefore, the research focus on the thermal behaviour of rock is important for the safety and maintenance of underground applications. A good deal of research has been conducted so far about the thermal behaviour of rocks. The existing literature on the thermal behaviour of rocks in Australia is currently restricted to a few regions, largely in New South Wales and Victoria. The literature suggests that the mechanical properties of heated rock behave differently due to various geological and stress conditions, even for the same rock types. The thermal behaviour of common rocks (basalt, argillite, and sandstone) in South East Queensland has not yet been identified. The aim of the present research is to study the thermal behaviour of common rocks in South East Queensland and to develop a damage model. In this, the physical and mechanical properties of thermally treated rocks have been investigated by conducting porosity tests, point load tests, uniaxial compressive strength tests, and triaxial tests. These outcomes were further examined in X-ray diffraction (XRD), thermogravimetry (TG), differential scanning calorimetry (DSC), derivative thermogravimetry (DTG), scanning electron microscopy (SEM) and micro-computed tomography (CT) analyses of the mineral composition and microstructure. It was found that the mineral composition and microstructure determine the engineering properties of rock under high temperatures. The critical temperature obtained using a thermal damage coefficient may vary significantly from the threshold temperature, and thus, for deep geological applications, it is recommended to determine both parameters. It was observed that high temperature treatment can significantly affect rock damage, more so than thermal cycle treatment. To predict the total damage of the rock, a thermomechanical damage model was proposed and applied to sandstone. This research will contribute to both theory and practice by providing a laboratory database, empirical correlations, and coupled thermo-mechanical damage model for common rocks in South East Queensland. More importantly, the outcome of this research will help to enhance the safety of deep underground projects.