Japan, the only country to have been subjected to nuclear strikes, has strongly advocated non-proliferation and arms control since WWII, and is a signatory to the Nuclear Non-Proliferation Treaty. However, the recent nuclear test carried out by nearby North Korea has provoked a debate among Japan's leadership over the country's nuclear status.
Taro Aso said Tokyo will not necessarily give up its long-standing principles: not to possess, produce or buy atomic weapons, but should nevertheless put the issue up for discussion, as Japan remains the only world power never to have considered owning nuclear weapons.
On Saturday the UN Security Council unanimously voted to pass a resolution imposing sanctions on North Korea following its test nuclear explosion.
Russian defense minister Sergei Ivanov earlier said that including the five official and four non-official nuclear club members, a total of 25 countries could potentially develop nuclear weapons.
Aso's statements echoed Shoichiro Nakagawa, policy chief of the ruling Liberal Democratic Party, who said Sunday that Japan's constitution does not completely exclude a nuclear option.
But Prime Minister Shinzo Abe said later on Sunday that Japan would stick to its self-imposed nuclear-free principles.
Japan is a party to the six-nation talks involving also North Korea, South Korea, Russia, China and the United States aimed at persuading Pyongyang to give up its controversial nuclear program.
The talks were launched in 2003, when the North withdrew from the Nuclear Non-Proliferation Treaty, but stalled last November over Pyongyang's demands that the U.S. lift sanctions imposed on it for its alleged involvement in counterfeiting and other illegal activities.
