But those worrying sunspots are not always dangerous. And a decision to have them cut out often results in unnecessary surgery and personal trauma.

It's a wise move to have any sunspot, particularly one that has changed in size or colour, checked by a doctor, but often it's not necessary to cut them out.

However doctors haven't had an accurate and quick way of diagnosing the problem area. That is up till now.

This is the Skin PolarProbe developed by Polartechnics, the Melanoma Unit at Sydney's Royal Prince Alfred Hospital and CSIRO.

The probe is pointed at the problem spot, capturing a picture which is stored on a personal computer.

The image is magnified and enhanced.

Then using software devised by CSIRO, the doctor is able to tell whether the spot is likely to be a melanoma or not.

"If a GP has a Skin PolarProbe, the patient should be able to go to that GP, have that image captured and have the diagnosis peformed immediately and if it's a melanoma have it excised straight away. "

It increases the rate of correctly diagnosing a melanoma, reducing the number of unnecessary removals.

Doctors can also plot various skin lesions on the patient's body, to keep watch on them over a period of time, in case they change and become cancerous.