Officials are likely to start discussions on possessing nuclear-powered submarines, whose ability to undertake long military operations secretly will help strengthen deterrence against China's maritime assertiveness.

The ruling Liberal Democratic Party and Japan Innovation Party (Nippon Ishin no Kai), as part of their coalition agreement in October, pledged to promote the country's possession of submarines powered by a next-generation energy source and equipped with a vertical launching system, or VLS, for long-range missiles.

Defense Minister Shinjiro Koizumi said on television on Thursday that "the environment surrounding Japan is so severe that we have to discuss whether to use diesel as we've done so far or nuclear power."