People are being warned to avoid touching possum faeces because of the risk of being exposed to a bacteria linked to flesh-eating ulcers.

Infectious disease researchers at Victoria's Barwon Health have found that possums can carry the buruli bacteria, which can cause major skin ulcers in humans.

Barwon Health Associate Professor Daniel O'Brien said possum faeces is rich in the bacteria.

He told 774 ABC Melbourne there needs to be more research into whether contact with possum faeces is what causes buruli ulcers, also known as Bairnsdale ulcers, in humans.

"What we know in areas where we're getting infections and possums are infected is that their possum poo does carry a large amount of the organism," he said.

"What we do think is a good public health measure is to remove the possum faeces from the area as much as possible and wash your hands as much as you can after that to minimise potential exposures."

The infection starts as a painless or itchy pimple, which then breaks down to form an ulcer. If untreated, the ulcer can spread.

Professor O'Brien said although curable, the condition can be serious.

"The treatment is really quite difficult," he said.

"It often involves a long period of antibiotics which can be difficult to take and often involves surgery."

He said people have been infected in Victoria's Gippsland region and the Bellarine Peninsula, and most recently in the Mornington Peninsula.

No infected possums have been detected in metropolitan Melbourne.

Professor O'Brien said a better understand of the bacteria's transmission is needed.

"The most important thing for me is that we can prevent this infection, because at the moment we can treat it but we don't really know how to prevent it," he said.

"When you see young kids coming into the clinic with really nasty ulcers on their arm ... what we really need to do is stop them getting it in the first place."