A Japanese military official stands upon their arrival on the apron of Banda Aech
airport in Indonesia, Jan. 16, 2005. (CNN) From News.com.au - NORTH Korea’s announcement today that it had tested a nuclear bomb is set to push Japan to expand its own military and stir debate on what was once the ultimate taboo of developing atomic weapons itself.

The test comes with Japan in the midst of expanding its defence posture, 60 years after it was defeated in World War II and forced by the US to renounce the right to a military.

Prime Minister Shinzo Abe, who took office just two weeks ago, is a sworn hawk on North Korea who has long supported a larger role for Japan’s military alongside its ally the US.

“North Korea’s nuclear weapons test can never be pardonable. But we should collect and analyze more intelligence on the matter in a cool-headed manner,” Mr Abe said today as he visited Seoul, according to a report.

In Tokyo, Chief Cabinet Secretary Yasuhisa Shiozaki, the spokesman for Mr Abe’s spokesman, said a North Korean test would post a “grave threat to stability in Northeast Asia” and that Japan would lodge a strong protest if it is confirmed.

Analysts expect North Korea’s test to boost the hand of Mr Abe, who wants to rewrite the pacifist 1947 constitution and allow Japanese troops to engage in overseas operations alongside allies.

Despite its pacifism and US guarantees to protect Japan, the country now has around 240,000 troops on active duty and an annual military budget of 4.81 trillion yen (US$41.6 billion).

A draft new constitution would preserve Japan’s official pacifism but acknowledge it has a military – and not the “Self-Defense Forces” as they are currently known.

Japan has already been taking a larger international military role. It sent a small but symbolic reconstruction mission to Iraq, the first time since World War II that Tokyo has deployed in a country where fighting is under way.

Japan is also believed to be capable of assembling nuclear weapons if it makes the political decision to do so.

But it would be a drastic change of policy for Japan, the only nation to suffer nuclear attack, which has long campaigned to eliminate atomic weapons.

More than 210,000 people were killed in the 1945 US atomic bombings that flattened Hiroshima and Nagasaki.

“I can’t reject the possibility that a nuclear deterrent system would be developed in the region,” said Yoshinobu Yamamoto, a professor of international politics at Aoyama Gakuin University.

“Even if the North’s missiles do not reach the United States, they could easily put Japan in the firing range and destroy it,” he said.

Former prime minister Eisaku Sato proposed developing nuclear weapons in the 1960s as China built the bomb. But his position was rejected by the US, which provides a security umbrella over Japan.

More recently, a magazine this year quoted Foreign Minister Taro Aso as telling US Vice President Dick Cheney that Japan would need atomic weapons if North Korea pursued a nuclear program. Aso’s aides denied the report.

Most Japanese support some revision to the constitution. But the country is sharply devided on how far to deviate from official pacifism.

A recent study by a US House of Representatives committee on intelligence said that Japan – and also South Korea and Taiwan – could be driven to pursue nuclear weapons if North Korea tested an atomic bomb.