The 2019-20 'Black Summer' fires were the most extensive, and among the more severe in recorded history. The long-term consequences of these fires for ecosystem sustainability are poorly understood, despite potentially far-reaching consequences for biodiversity conservation, cultural values and essential ecosystem services. To improve understanding of which ecosystem types are affected, how the fires contribute to long term risks and develop risk-reduction strategies, we applied a diagnostic risk-based approach to rainforests and peat-accumulating ecosystems, two of the most unique and potentially fire-sensitive groups of ecosystems on the Australian continent. We make several recommendations to secure the contributions of Australian ecosystems to biodiversity conservation and human well-being into the future.