Japan, Australia and regional security architecture

Greetings from the Australian National University in Canberra where I am attending a panel discussion on "Japan, Australia and regional security architecture". Dr Amy King (ANU), with Professor Mie Oba (Tokyo University of Science), Associate Professor Ryo Sahashi (Kanagawa University), and Professor Nick Bisley (La Trobe University) are discussing Japan and Australia's role in regional security institutions, including  ASEAN Regional Forum, ASEAN Defence Ministers Meeting Plus, and East Asia Summit. But it quickly become evident that the real topic was what Japan and Australia could do about China claims to islands in the region. The claim was made by one of the panelists that Australia is not directly involved in the dispute. However, I suggest it is, in that RAAF aircraft are flying over some of the islands, in a direct military challenge to China's claim of sovereignty. I am not a foreign policy expert, but it seems to me that one effective initiative for Japan and Australia is to build more submarines. Forums, Meetings and Summits have no effect, unless they can be backed by a credible military force.