Japan has no effective means of protecting its citizens in the event of a ballistic missile attack by North Korea, Defense Agency chief Shigeru Ishiba said Monday.

"All we could do is minimize the damage if a missile is fired against Japan," Ishiba told the House of Representatives Budget Committee when asked by an opposition lawmaker how Japan would respond to a ballistic missile attack.

If Pyongyang test-launches a ballistic missile over Japan, as it did in 1998 with the Taepodong launch, the government would immediately relay pertinent information about it to the public, Ishiba said.