Japan's major ruling party plans to consider revising the country's pacifist constitution, according to the Chief Cabinet Secretary Yasuo Fukuda.
Japan's sophisticated military is currently very restricted
Mr Fukuda said on Tuesday that the ruling Liberal Democratic Party (LDP) would aim to draw up proposals by the 50th anniversary of the foundation of the party, in 2005.
Article Nine of the constitution, which was written under US post-war occupation in 1947, renounces the use of force by Japan in settling international disputes.
There are growing fears in Japan that neighbouring North Korea is pursuing a nuclear weapons programme, and that Japan could be at risk of attack. However, a recent poll showed that only 42% of people favoured a revision of Article Nine, according to Reuters news agency.
Many fear that changes to the constitution could lead to a revival of the militarism which dominated Japan in the run-up to World War II.
Mr Fukuda said Japanese Prime Minister Junichiro Koizumi had approved the plan, as a means of sparking debate on the issue.
Bur Mr Koizumi denied it would form part of his re-election manifesto.
He is due to start campaigning on 8 September for the LDP leadership election later that month.
Mr Koizumi has already pushed for a strengthening of the country's missile defences and a greater role for Japanese peacekeepers.
Earlier this year, Japan's parliament passed three bills which gave the government more powers to respond to an attack on Japan.
And local media reported on Friday that Japan's Defence Agency had decided to request 144bn yen (US$1.12bn) from the government to develop an
anti-missile defence system, the Nihon Keizai business
newspaper reported, citing unnamed sources.
The budget request for the next fiscal year would be nearly nine times the 15.6bn yen (US$132m) Tokyo spent on missile defence research from 1999 to 2003, according to the Associated Press.