Fire is one of the most notorious hazards in Australia, with important economic impacts and damage to ecosystems. There is a concern of worsening fire conditions under climate variability, but there is little understanding of the variability in fire occurrence related to climate patterns. We present a statistical decomposition for spatio-temporal analysis of changes in fire occurrence in Australia and its association with climate factors. We found evidence of variability in the trend results for fire occurrence, and also some evidence that this variation is related to climate patterns. Our approach has applicability to other climate-related issues, providing a useful tool to identify possible changes in the intensity of occurrence over time, capturing long-term changes, and also seasonal and cyclical effects.