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

The Victorian government sat on a report for more than 12 months that found the state’s koala population was in chronically poor health.

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.

It estimated there were 217,000 koalas in the state in 2023 and 224,800 in 2024—a dramatic drop from past estimates of 460,000, which the report attributed to different survey and modelling methodology, rather than an actual population decline.

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 euthanized on welfare grounds."

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."