TOKYO - JAPAN'S parliament on Friday extended a naval mission backing US-led operations in Afghanistan by another year, relieving one headache for beleaguered conservative Prime Minister Taro Aso.

The lower house, where the ruling coalition holds a commanding majority, used its power to approve the bill by overriding the opposition-led upper house which voted down the bill earlier in the day.

The mission, which was due to expire in January, provides fuel and other logistical support on the Indian Ocean to the US-led coalition.

Mr Aso supports a more active security role for Japan, which has been officially pacifist since its defeat in World War II.

The opposition, which is rising in the polls, says Japan should not be part of 'American wars' and should instead focus on humanitarian reconstruction in Afghanistan.

'We will assume our responsibility in the international community by continuing our part in the war on terror through the refuelling mission,' Mr Aso said in a statement after the legislation's approval.

'Japanese forces, who are operating in the Indian Ocean under harsh circumstances, make Japan proud,' Mr Aso said.

Mr Aso took office in late September in hopes of leading his long-dominant Liberal Democratic Party into elections, but his approval rating has rapidly fallen as the world's second largest economy falters.

Mr Aso was expected later on Friday to unveil a bigger package to help Japan weather the global financial crisis.

The sharp-tongued prime minister has also lost support by making a series of offensive remarks, including criticising the elderly in the rapidly greying country for not staying physically fit.

Some career diplomats and ruling party lawmakers worried a suspension of the Indian Ocean mission would hurt relations with the United States, Japan's main ally, as President-elect Barack Obama has pledged a new focus on Afghanistan.

Thomas Schieffer, the outgoing US ambassador to Japan, welcomed the parliament's decision.

'As a leading member of the international community, Japan has an important role to play in ... efforts to support a stable, democratic Afghanistan and in the fight against terrorism,' he said in a statement.

The opposition last year forced a temporary halt to the Indian Ocean mission by refusing to vote on it in the upper house.

This year, the opposition offered to vote the bill down - effectively letting it pass - in return for Mr Aso calling early elections or at least taking quick action on a new supplementary budget.

However, Mr Aso has indicated he is in no hurry to call elections or start debate on a new budget, which is separate from his emergency package.

The opposition accused Mr Aso of abusing his power by ramming through the bill.

'Forcing through the legislation with a two-thirds majority is a vicious act that tramples on the principle of democracy,' Mitsuo Mitani, an opposition lower house member, said in parliament before the vote.

The lower house also approved a law that allows the government to inject public funds into banks to help them prevent collapse. The upper house had voted it down, seeking greater regulation on two controversial lenders.

Japan must hold elections by September 2009. The last elections in 2005 gave the ruling party a huge majority on the popularity of then reformist premier Junichiro Koizumi.

The opposition says the ruling coalition should not use its sweeping majority in the lower house as it does not reflect the mandate of Mr Koizumi's three unpopular successors, including Mr Aso. -- AFP