Dr Stewart says few people see platypuses and even less spend time thinking about them.

"Most Tasmanians hardly ever see a platypus, let alone one with an ulcer," Dr Stewart said.

About 36 per cent of animals caught by researchers have ulcers, which have been caused by the fungal infection Mucor amphibiorum.

The fungus was first detected in Germany in 1974 and has since been found in amphibians, including green tree frogs and cane toads, in most parts of Australia.

It was first identified in Tasmania in the 1990s and has now been found right across the central north of the state. Tasmania is the only place the fungus has been detected in platypuses.

Dr Stewart said fungus diseases were usually opportunistic and developed on hosts with immune system problems.

Among the possible causes of immune system problems were man-made chemicals, including polychlorinated biphenyls (PCBs), dichloro-diphenyl-trichloroethan (DDT) and Hexachlorocycloheaxane (Lindane).

PCBs are used in transformer oil, paints and plastics.

They were banned in the US in the 1970s but low level PCB oils are still in use by the Hydro in Tasmania.

DDT, banned in 1987, and Lindane are insecticides which have been used in Tasmania. The chemicals tend to bioaccumulate in animals high on the food chain.

Dr Stewart said PCBs, DDT and Lindane were all found in the tailfat of the state's platypuses.

"PCBs and DDT are present at quite high levels in some areas," Dr Stewart said.

"But probably not high enough to cause immunosuppression."

He said high levels of PCBs were found in platypuses in areas without the fungal infection, which suggested the chemical pollution was not involved in the disease.

Dr Stewart said the disease had the potential to greatly affect the state's frogs.

"At the moment there is no research at all being done," Dr Stewart said.

"There hasn't been any research done since 2002.