Foreign Minister Nobutaka Machimura said the United Nations had asked Japan to send troops for a potential mission in Darfur, where Arab militias backed by the Sudanese government have waged a bloody crackdown on rebels.

"All the affected agencies and ministries will start discussions," Machimura told reporters.

The Mainichi Shimbun said Japan was studying whether its troops in Darfur should help disarm combatants and monitor a truce in Darfur, in a much riskier mission than Tokyo's previous peacekeeping assignments.

The daily, which did not identify its sources, said the government believed such a mission would help Japan lobby for its cherished goal of a permanent seat in an enlarged UN Security Council.

Defense Agency chief Yoshinori Ono said: "Activities in the arena of international peace should improve Japan's image."

But Kaoru Okano, political scientist and former president of Meiji University in Tokyo, questioned whether more military activity would help Japan's UN bid, which is backed by the United States but not China.

"Consider China. They don't want to see Japan playing expanded military roles," Okano said.

China has a veto on the Security Council and has indicated it opposed giving Japan the same power, saying Tokyo has yet to make amends for its wartime aggression in Asia.

Japan renounced the right to use force and maintain a military in its 1947 constitution imposed by the United States after World War II.

But Tokyo has recently been trying to increase its international profile through military operations to prove that it is more than a financial power.

Japan has some 550 troops in the southern Iraqi city of Samawa on a non-combat, humanitarian mission in Japan's first military deployment since 1945 to a country where there is active fighting.

Last month, Japan deployed a 950-member contingent to Indonesia to help relief after the tsunami disaster in the country's largest overseas military deployment since World War II.

Japanese troops have also taken part in UN peacekeeping operations in Cambodia, Mozambique, the Golan Heights and East Timor, but their activities were mostly been confined to logistics such as transport.

The Mainichi said the mission would be far more active in Darfur, where around 70,000 people are estimated to have died since February 2003 in fighting, hunger and disease.

Members of the UN Security Council have called for a peacekeeping force to be sent to Darfur once a peace deal is sealed between the ethnic rebels and the pro-government Janjaweed militias

A ceasefire is in place, but some 100 people were killed last week in a government air raid near the town of Shangel-Topayi, according to the African Union, which has about 1,700 peacekeeping troops on the ground.