A report commissioned by the Victorian government has revealed the state’s koala population is in significantly poorer health than previously understood and may be roughly half the size earlier estimates suggested. The assessment, completed by the Arthur Ryjah Institute alongside university researchers and finalized in June 2025, estimates between 217,000 and 224,800 koalas in Victoria during 2023 and 2024. This figure contrasts sharply with prior estimates of around 460,000, a discrepancy attributed primarily to more rigorous survey and modelling methodologies rather than a sudden population decline.
The study involved systematic visual and acoustic surveys of koalas across 182 sites statewide, marking the first comprehensive statewide population assessment. As part of the health evaluation, 68 koalas underwent clinical examinations, with 29 individuals (43%) euthanised due to severe health issues. Researchers found a notably higher proportion of koalas in chronically poor condition across seven geographically distinct regions.
Key health concerns included poor body condition, dental disease, and advanced urinary tract infections commonly associated with chlamydia. Dental disease was recorded in 37% of the sampled koalas, except those from Mallacoota. The researchers warned these conditions likely arise from multiple overlapping stressors affecting koalas’ physiological wellbeing across all life stages.
Leanne Wicker, a wildlife veterinarian involved in the study, described the findings as alarming and said the poor health observed in many koalas indicated an urgent need for ongoing research and support. She noted that localized areas with high koala densities, such as French Island and parts of western Victoria, had contributed to a false sense that the state’s overall koala population was stable and thriving. However, the report emphasizes that many regions experience low koala densities and poor welfare, suggesting localized population declines could go unnoticed.
Desley Whisson, a co-author from Deakin University, underscored concerns about low-density regions where koalas may be at risk of unnoticed losses. The report also indicates that about 23% of Victoria’s koalas now inhabit blue gum plantation estates, where population densities are significantly higher compared to neighbouring native forests, raising questions about the impact of plantation management on koala survival.
In response to the report’s findings, new environment minister Jaclyn Symes announced a $2.6 million funding package aimed at koala conservation, which includes habitat restoration and advancing research into koala health and genetics. A department spokesperson highlighted that the government had been consulting with various agencies and stakeholders since receiving the report, with the recent funding announcement reflecting a prioritisation of the report’s recommendations.
The delayed public release of the report—held back for more than a year—drew criticism from conservation advocates, including Koala Alliance representative Jessica Robertson, who described the hold-up as a failure in transparency and a missed opportunity to address koala welfare. Meanwhile, Animal Justice Party MP Georgie Purcell emphasised the urgency of intensified conservation efforts to prevent Victoria’s koalas from facing the same endangered status observed in other parts of Australia. The environment department has stated that ongoing koala health management work was not impeded by the report’s timing.