Japan will step up its efforts to build a next-generation missile shield with the United States after cabinet approved on Saturday to move a joint research project to the development stage.
The system is seen as a measure against nuclear-armed North Korea's ballistic missile arsenal, and Tokyo and Washington began studying the project shortly after Pyongyang test-fired a missile over Japan in 1998.
"In order to secure a capability to deal with the future threat of ballistic missiles in the current global environment, it is appropriate to proceed with joint Japan-US development," Japan's top government spokesman, Shinzo Abe, said in a statement.
Experts say it would take only about 10 minutes for a North Korean missile to reach Japan, and public concerns about the threat have risen after Pyongyang declared in February for the first time that it had nuclear weapons as well. The next round of six-country talks aimed at ending North Korea's weapons programme is likely to held in January, but no date has been set yet.
Tokyo eased a blanket ban on arms exports last year to open the way for the joint development project with Washington.
Japan has already spent about 26 billion yen ($221.5 million) for joint research on the system, and another 3 billion yen ($25.56 million) was set aside in the budget for the upcoming fiscal year, which was approved by the cabinet on Saturday. The fresh funds would be used to develop an upgraded version of the Standard Missile-3 (SM-3) interceptor missile, which officials said would likely go into production around 2016, and be installed on US and Japanese destroyers.
The development of the missile would cost about $2.1 billion to $2.7 billion over nine years, of which between $1 billion and $1.2 billion would likely be paid for by Japan, Japanese defence ministry officials have said.
North Korea has criticised Tokyo's plans as a provocation and other countries in the region including China and Russia have expressed concern that the missile shield would be used to keep their military capabilities in check.
But Japanese officials have said establishment of a missile defence system is in line with Japan's policy of keeping its military activities and capabilities purely defensive.
Apart from the joint project with Washington, Japan decided in 2003 to buy a missile defence system from the United States based on the current Patriot 3 (PAC-3) surface-to-air missile, and the system is set to be deployed from around 2010.