Doctors have been urged to refer melanoma patients to Australian radiotherapy trials, which are being forced to study patients from overseas.

Overseas skin cancer patients are being used in Australian radiotherapy trials due to a lack of local volunteers, a researcher says.

Professor Gerald Fogarty is calling on more Australian doctors to refer patients onto the multiple trials investigating the effectiveness of radiotherapy for people with melanoma.

"It really is our responsibility to provide this evidence for the world as Australia has the highest skin cancer incidence in the world," he says.

Prof Fogarty, from Genesis Cancer Care NSW, is presenting an overview of current studies to the Clinical Oncology Society of Australia's annual scientific meting in Hobart.

Evidence on the use of radiation in melanoma treatment was desperately needed, he said.

"My colleagues and I are conducting randomised controlled trials for melanoma primary sites and also when the cancer has spread to regional lymph nodes and distant sites," he said.

One trial is evaluating the effectiveness of whole brain radiotherapy for patients whose melanoma has spread to the brain.

"Generally speaking, it's difficult to find Australian doctors willing to suggest the trial to patients and we are now working with patients from Norway and UK in order to get a large enough research sample," he said.

"This is a controversial area and often clinicians are reluctant to steer away from proven treatment methods such as brain surgery."

But he said the research was needed so treatment can evolve and patient outcomes can improve.