Over the next two or three weeks, Japanese Prime Minister Shinzo Abe's Cabinet is expected make a decision on whether to revise the government's stance on Japan's right to exercise collective self-defense, said a key security adviser to Abe on Wednesday.

In an interview with Reuters, Shinichi Kitaoka said Japan should change its constitution to allow its military to defend not only its ally the United States, but also other countries close to it.

If so, this would be a step further than expected.