Australian energy markets, like EU markets, have been administratively led over recent decades to create more competitive markets. There have been many inquiries and reports by Australian government agencies on regulatory, economic and competition law aspects of energy markets. A recent controversial report by the competition agency recommends increased price regulation of natural gas pipelines on the grounds, not of enhancing competition, but of ameliorating market power of pipeline operators, to create perceived efficiency benefits in downstream and upstream markets. The change in emphasis from 'competition' to 'efficiency' raises important issues for the energy sector and competition law generally in Australia because market power is traditionally assessed by reference to structural analysis, and the institutional framework generally limits the jurisdiction of Australian courts to 'competition' assessment while conferring jurisdiction on administrative agencies to assess 'efficiency'. This article discusses the competition law implications of these recent developments for the energy sector, particularly natural gas, with respect to market power and access to facilities, having regard to EU and US third-party access regimes.