Asian nations are investigating the possibility of a 16-nation free-trade area following a Japanese proposal to the Association of Southeast Asian Nations (Asean). Although experts warned years of distrust and protectionist policies are likely to pose significant barriers to the plan, Tokyo wants experts to begin studying a trade zone that would also include China, India, South Korea, New Zealand, Australia and Asean's 10 members, the Wall Street Journal reported. The 16 countries include 3.1 billion people and combined gross domestic product of almost US$10 trillion per year. The move comes as members of Asean moved up the deadline to create a seamless market throughout the association's own members from 2020 to 2015. The move may be a serious attempt to counter the economic challenges posed by China and India.