From www.smsfadviser.com: The Superannuation (Industry) Supervision Act defines a dependant as a person who is the spouse, child, or has an interdependency relationship with another person, including financial dependency.

An interdependency relationship exists if two individuals share a close personal relationship, live together, and provide each other with financial and domestic support.

Various factors, such as emotional support and mutual commitment, can determine if such a relationship is established, and financial support must be significant to qualify as dependency under SISA.