Victoria’s koalas in chronically poor health and population is half what was previously estimated

The review of the state’s koala populations, led by state science agency the Arthur Rylah Institute in conjunction with scientists from major universities, was completed for the Victorian government in June 2025.

The report used systematic visual and acoustic surveys in 2023 and 2024 to monitor koalas at 182 sites, and its data was then used to estimate the overall abundance and distribution of Victoria’s koala population. As part of the research, scientists conducted health and disease assessments on 68 koalas, with 29 of the koalas (43%) found to be in such poor health they “were euthanised on welfare grounds”.

The government published the report on Wednesday morning as the new environment minister announced $2.6m for koala conservation, including for habitat restoration and research into koala health and genetics. The report warned the surveys found “a higher-than-expected proportion of koalas from seven geographically distinct regions in a state of chronically poor health and welfare”.

A wildlife veterinarian who was one of the authors on the report, said researchers had been shocked by the poor health of some of the koalas they found in the field, remarking that it’s been very difficult to get the support and resources needed because the report hadn’t been made public.