What super obligations do I have for contractors?
If you pay your contractors under a contract that is wholly or principally for labour, you have to pay super contributions for them. This is even if the contractor quotes an Australian business number (ABN). These contractors are considered your employees for Superannuation guarantee purposes.
Generally, a contract is principally for labour if more than half of the value of the contract is for the person’s labour, which may include:
The Australian Tax Office have web-based tools to help you work out if someone is an employee or contractor, and if they are eligible for super contributions at:
http://www.ato.gov.au/businesses/content.asp?doc=/content/19159.htm