Treaties allowing investors to initiate arbitration claims directly against host states for illegally interfering with cross-border investments are becoming increasingly common in Asia, but Australia announced in 2011 that it will no longer include such protections in future treaties. The backdrop to this decision includes keen interest from Asia in foreign direct investment (FDI) into Australia’s resources sector, meaning that potential investors may not be significantly deterred by a lack of arbitration provisions in future treaties. This article argues, however, that Australia’s policy shift risks undermining the entire investor-state arbitration (ISA) system, with the earliest impact being felt by major pending treaty negotiations by Australia with Japan, China and Korea (respectively); and that the shift may significantly reduce FDI flows or have other adverse effects. The article criticises the cost-benefit analysis of ISA protections in one pivotal study conducted in 2010 by an Australian Government think-tank, arguing that this assessment is insufficiently nuanced. Instead, the article presents a justification for more tailored and moderate changes to ISA provisions in future treaties. Its tentative interest-group analysis suggests, however, that there may be surprisingly few public or private constituencies that would prefer such moderate reforms, and that most may well prefer the more extreme position recently adopted by Australia, despite the damage that will be done to the ISA system as a whole. The article also argues that Australia’s policy shift and think-tank analysis may make Asian countries more cautious about ISA, especially those (like the Philippines and Vietnam) which have traditionally been more cautious about this dispute resolution system. [ABSTRACT FROM PUBLISHER]