A dead koala has been found between fallen trees in a logged forest that the Andrews government could have protected – had it not ignored advice from its own scientific committee.

The Sunday Age has obtained graphic images of the lifeless animal slumped over branches in the Acheron Valley north of Warburton, in a confronting example of the potential impact of logging in Victoria.

A department investigation is now under way, as Premier Daniel Andrews faces renewed calls to create a Great Forest National Park, to curb what some claim is the "senseless slaughter" of native animals and the environment.

VicForests has also vowed to conduct a review once it has the full details, with acting chief executive Nathan Trushell saying on Saturday: "If this is one of our operations, we deeply regret that this occurred."