But on Tuesday Yasuo Fukuda, the Japanese prime minister, saw a revised bill authorising a resumption of refuelling operations pass through the government-controlled lower house of parliament.


The bill now goes before the opposition-dominated upper house, where it is expected to get a rougher ride.


The issue has become the focal point of a fierce national debate over Japan's international responsibilities and the role of its armed forces.


The opposition won control of the upper house of parliament in July elections and has vowed that Japan, which has been officially pacifist since the end of World War Two, should not take part in what it calls "American wars".


Fukuda is preparing for his first
summit with President Bush [AFP]
That stood in stark contrast to Fukuda's predecessor, Shinzo Abe, who had been an outspoken advocate for a more robust, activist Japanese foreign policy.


Abe resigned in September after just under a year in office, in part due to the opposition's blocking of an extension to the naval mission.


Now, there is mounting speculation that Fukuda will call a snap general election if the opposition again moves to block the deployment.


But there are signs of cracks in the opposition.


Earlier this month Ichiro Ozawa, the leader of the main opposition Democratic Party of Japan (DPJ), threw his party into disarray by considering Fukuda's offer to enter into a grand coalition.


Ozawa said he would step down but retracted his offer two days later.


Fukuda's drive to see the naval operation reinstated comes as he prepares to travel to Washington later this week for his first summit meeting with George Bush, the US president.