Use sunscreen, even if your birth mark gets a sunburn. It will protect other areas of skin.

Stay out of the mid-day sun. UV radiation is the most intense during the middle of the day when the sun is nearly overhead.

When you do go out in the sun, wear light clothes that cover your birth mark, as well as other areas. Find and use a broad-brimmed hat.

The Aussies are very much aware of the dangers of skin cancer. You should be able to find all of this, as well as more information when you get there.