Defense Minister Itsunori Onodera visits the U.S. military’s Aegis Ashore test site in Kauai Island, Hawaii, on Jan. 10. (Ryo Aibara)

HAWAII--In a comment likely to spark controversy over the nation's defense policy, Defense Minister Itsunori Onodera on Jan. 10 said Japan should build a comprehensive system capable of intercepting cruise missiles.

Japan will introduce the Aegis Ashore, the land-based version of the missile defense system, to deal with the increasing threat from North Korea, which has tested ballistic missiles in recent years.

Onodera’s comment suggests that Japan should expand the Aegis Ashore to be prepared for possible cruise missile attacks.

Among countries close to Japan, China is known to be putting muscle into the development of cruise missiles that can travel faster and have a range longer than conventional ones.

The defense minsiter’s remarks on boosting Japan’s missile defense capabilities came after his first visit to the U.S. military’s Aegis Ashore test site in Kauai Island in Hawaii.

Calculating the trajectory of a ballistic missile is expected to be relatively simple as it flies in a parabolic curve.

But shooting down a cruise missile would pose a much greater challenge as it can change course in flight and is harder to detect on radar as it flies at a lower altitude.

The Japanese government is leaning toward the inclusion of the Integrated Air and Missile Defense (IAMD), the envisaged missile defense system laid out by the U.S. military, in the National Defense Program Guidelines, which is expected to be revised this year.

The IAMD is targeted at not only ballistic missiles but also cruise missiles and other aerial threats.

Some defense experts say the SM-6, the next-generation interceptor missile, can shoot down a cruise missile if it is deployed to the Aegis Ashore.

Calls are growing from the Defense Ministry that Japan should respond to China’s cruise missile program in the future.