Dermatologists say new research shows almost half of all melanoma deaths are from lumps that look like innocent pimples, rather than skin cancer.

Australia has the highest rate of melanoma in the world and now dermatologists say almost half of those deaths are from lesions which do not present as typical skin cancers.

Associate Professor John Kelly from the Victorian Melanoma Service says many doctors are dismissing the lumps, which are round and red or brown but which are in fact melanoma.

He says to bring down the death rate, doctors and patients need to be more aware of the spots, which grow quickly and can be easily mistaken for moles or pimples.

Melanoma is the least common type of skin cancer, but the fourth most common cancer in Australia with more than 12,500 new cases diagnosed in 2012.

It is the most dangerous form of skin cancer and is the seventh most common cause of cancer death in Australia.

People with fair skin are also at higher risk.