Federal and state laws appear to be inconsistent on whether non-lawyer tax agents can advise clients about trusts or supply clients with trust deeds. Trust-related tax agent services are both authorised and prohibited. Broad and narrow formulations of unauthorised legal practice under state law proscribe this tax agent activity. Supply of trust deeds and related advice is more than incidental to the tax advice and representation services which federal law authorises tax agents to supply. Consumer protection rationales and practical applications of the state law prohibitions are examined. It is concluded that tax agents who provide trust deeds and advice about trusts will sometimes be engaged in unauthorised legal practice.