Washington's strategic ambitions in Asia are looming large over Australia's multibillion dollar tender for new submarines, giving Japan a possible edge over competitors from Germany and France, defense and industry sources say.

Although the United States had little presence at a conference last week in Adelaide, Australia, convened to discuss the project, the enthusiasm U.S. commanders have shown for Canberra buying Japanese submarines was one of the hottest topics behind the scenes.

Such a purchase would bind the American, Japanese and Australian navies more tightly together in the face of China's rapid military modernization and growing assertiveness in Asian waters.