TOKYO: Japan on Friday said it will develop new "stand-off" anti-ship missiles that will allow it to target warships at greater distances around its southwestern Okinawa island chain, including disputed islets in the East China Sea that China also claims.

"The security environment around our southwestern islands has become harsh. We have to respond to that in an appropriate way," Japanese Minister of Defence Nobuo Kishi said at a press briefing.

The missiles would allow Japan to expand a strategy known as anti-access area denial (A2AD), that is meant to stop foreign forces from operating freely in waters close to home territory.

The decision comes as Japan acquires air-launched missiles that could be used to hit ballistic missile launchers in North Korea and is considering other strike weapons such as cruise missiles that would have enough range to target sites in China.

Japan also said on Friday it planned to put new powerful Aegis radars with at least three times the range of older Aegis systems on two new warships in order to reinforce defences against any ballistic missiles fired by North Korea.