Japan and the United States are exploring the possibility of Tokyo acquiring offensive weapons that would allow Japan to project power far beyond its borders.

Japan and the United States are exploring the possibility of Tokyo acquiring offensive weapons that would allow Japan to project power far beyond its borders, Japanese officials said, a move that would likely infuriate China.

While Japan's intensifying rivalry with China dominates the headlines, Tokyo's focus would be the ability to take out North Korean missile bases, said three Japanese officials involved in the process.

They said Tokyo was holding the informal, previously undisclosed talks with Washington about capabilities that would mark an enhancement of military might for a country that has not fired a shot in anger since its defeat in World War Two.

The talks on what Japan regards as a "strike capability" are preliminary and do not cover specific hardware at this stage, the Japanese officials told Reuters.

Defense experts say an offensive capability would require a change in Japan's purely defensive military doctrine, which could open the door to billions of dollars worth of offensive missile systems and other hardware. These could take various forms, such as submarine-fired cruise missiles similar to the U.S. Tomahawk.

U.S. officials said there were no formal discussions on the matter but did not rule out the possibility that informal contacts on the issue had taken place. One U.S. official said Japan had approached American officials informally last year about the matter.

Japan's military is already robust but is constrained by a pacifist Constitution. The Self Defense Forces have dozens of naval surface ships, 16 submarines and three helicopter carriers, with more vessels under construction. Japan is also buying 42 advanced F-35 stealth fighter jets.

Reshaping the military into a more assertive force is a core policy of Prime Minister Shinzo Abe. He has reversed a decade of military spending cuts, ended a ban on Japanese troops fighting abroad and eased curbs on arms exports.