Employers in Australia are required by legislation to make a payment to a nominated superannuation fund on behalf of their employees. This amount is usually a percentage of the employee's gross pay, and is subject to employment status (e.g. casual, full time) and their applicable award documentation. This obligation is termed the Superannuation Guarantee Levy (SGL).
See Superannuation Guarantee Levy
Above and independent of SGL, an employee can elect to make additional contributions to their nominated superannuation fund, out of their own wages / salary.
See Employee Personal Super Contributions
From 1 July 2005, certain employees will have the right to choose which superannuation fund or retirement savings account will receive their superannuation guarantee contributions. This is known as choice of superannuation fund.
See Super Choice