The juvenile male platypus was found dead earlier this month along Cockatoo Creek, about an hour's drive east from Melbourne.

A wildlife vet later confirmed its extensive injuries were consistent with a dog attack, Victoria's Conservation Regulator said on Monday.

Conservation Regulator senior investigator Mike Sverns said the platypus was a native species with a declining population and needed protection.

He said an investigation into the platypus attack was underway and urged the public to report any suspected wildlife crimes.

The maximum penalty for illegally hunting, taking or destroying protected wildlife is $8,261 and/or six-months in prison.

Wildlife ecologist Josh Griffiths said platypuses were extremely vulnerable to predation when crossing between bodies of water such as creeks and dams.

"It is imperative to keep dogs contained and under control around waterways," he said.

Australian Associated Press