Japan's powerful lower house of parliament Thursday approved a bill to upgrade Japan's Defence Agency to a full ministry so as to bolster the agency's status within the government.

Currently, Japan's military is strictly constrained by the country's pacifist constitution which Prime Minister Shinzo Abe has vowed to revise. The Defence Agency is part of the Cabinet Office rather than a separate ministry.

The bill was passed by the house's security committee earlier yesterday and is to be sent to the other chamber for further debate and a separate vote in coming weeks. But yesterday's passage by the lower house makes the bill's enactment almost certain because of the ruling bloc's domination in both houses.

The bill would make the defence forces' overseas peacekeeping activities a part of its regular duties, in addition to defence and disaster relief at home. Their overseas relief and humanitarian missions under United Nations' auspices are currently outside of the defence forces' core activities.

Chinese analysts yesterday expressed concern over the move, saying it would violate Japan's pacifist post-World War II constitution, which prohibits the use of force in solving international disputes.

Lu Yaodong, a researcher with the Chinese Academy of Social Sciences, said the upgrading would lead to a transformation in the role of Japanese defence forces.

He said the bill would make overseas missions a regular part of the Japanese armed forces duties, potentially heightening regional tension amid ongoing attempts to address the nuclear issue on the Korean Peninsula.

In a bid to boost its international profile, Japan sent non-combat troops to southern Iraq to help rebuild that country. Japan also approved late last month a one-year extension of its naval mission in the Indian Ocean to support the US-led anti-terrorism campaign in Afghanistan.

Both operations were criticized by some in Japan as violating the nation's constitution, which prohibits the use of force in solving international disputes.

"The bill would knock the bottom out of Japan's security policy and trample on the Article 9 (pacifist) clause of the constitution," said opposition Communist Party lawmaker Seiken Akamine. "The bill merely aims to send the defence forces abroad to back US-led war."

The agency is expected to become a ministry early next year.

Also yesterday, Japanese Foreign Minister Taro Aso said Japan has the technological know-how to produce a nuclear weapon, but has no immediate plans to do so.

Speaking to a parliamentary committee, he repeated the official government position that the country's pacifist constitution, which allows for the country to defend itself, does not forbid possession of an atomic bomb for defence purposes.