This dissertation critically evaluates the rationale for, and implementation of, the regulatory scheme governing third party access to essential infrastructure services (the 'national access regime') set out in Part IIIA of the Trade Practices Act 1974 (Cth). The analysis and synthesis of background reports, economic and legal theory, statutory provisions, existing case law, academic commentary and regulatory guidelines contained herein represents a useful and necessary contribution to this nascent area of Australian competition law. In particular, the comprehensive nature of the research has permitted informed assessment of the Productivity Commission's recent review of the national access regime and the Commonwealth Government's response to that inquiry. While the dissertation endorses both the Productivity Commission's finding that retention of the Part IIIA access regime is warranted and many of the (notably light-handed) recommendations advanced by the Commission to improve aspects of the regime's operation, it takes issue with the Commission's failure to propose a more substantial refashioning of the regime's architecture. Stepping into this breach, the dissertation specifies the systemic changes to Part IIIA that are imperative to enhancing the efficacy of the national access regime.