There are 3 stages to the production of sugar - growing, milling and refining.
In both Australia and New Zealand table sugar comes from the sugar cane plant. Sugar is made in the leaves of the sugar cane plant by photosynthesis.
During milling the cane is crushed to extract the juice. The juice is cleaned and concentrated into a syrup. Sugar crystals then form what is called 'raw' sugar. This is typically non-food grade.
At the refinery, the 'raw' sugar is converted to food grade products through a process that includes purification, cleaning and drying. The result is sugar ready for the consumer.