Scientists have identified a dramatic increase in the treatment of "pre-cancerous" melanomas that might not be harmful, according to new research.

The research out of QIMR Berghofer suggests many pre-cancers detected during routine skin checks may not have needed treatment or medical intervention.

Tracking four decades of long-term skin cancer trends in Queensland, Scotland and the United States, the QIMR study compared pre-invasive and invasive melanoma rates.

The results showed that rates of pre-invasive melanomas have risen faster than rates of dangerous melanomas across all three populations.

It also found patients with pre-invasive melanomas were, on average, several years older than those with invasive melanomas.

"Taken together, these findings strongly suggest that we are increasingly detecting and treating many lesions that ultimately would have caused no harm if they were left undiagnosed," lead researcher Professor David Whiteman said.

"It's a particularly pronounced trend in Queensland, where residents have long been aware of their high skin cancer risk, but our study shows it's also a rapidly emerging issue in the United States and Scotland."

Professor Whiteman says melanoma still claims thousands of lives each year and warns the findings should not negate the importance of skin cancer prevention, screening, and treatment.

However, it highlights the need for even better diagnostic tools to identify potentially lethal melanomas.

"Unnecessary melanoma diagnoses and surgeries can cause a lot of pain and anxiety for patients and also incur considerable expense to both individuals and healthcare systems," Prof Whiteman said.

"The holy grail of melanoma research is to develop a diagnostic tool that can reliably and accurately diagnose pre-invasive melanomas as harmful or benign, in the hope that we can spare some patients unnecessary surgery - and the suffering and expense that comes with it."

The study was published in the Journal of the National Cancer Institute.