The announcement came just ahead of US President Barack Obama’s visit to Tokyo on Friday and Saturday.

‘We will offer aid of up to five billion dollars over five years,’ the government said in a statement after the cabinet of centre-left Prime Minister Yukio Hatoyama approved the package.

Since coming to power in September, the Hatoyama government has said it will end a naval refuelling mission that has supported the US-led campaign in Afghanistan, but instead promised to step up aid.

The five billion dollars is likely to be disbursed through international organisations such as the UN Development Programme, said media reports.

The main pillar is assistance, such as job training, to help former Taleban soldiers return to mainstream society, and the redevelopment of the capital city Kabul.

The aid will also include salary payments for police officers and teaching programmes on rice farming and agricultural development.

‘We will provide our maximum support for the improvement of Afghanistan’s capability to maintain security,’ the government said. ‘It is necessary to set up a practical system in which former soldiers can return to society.’

Hatoyama confirmed Japan would not deploy troops to Afghanistan under the programme, as his left-leaning coalition partners have voiced strong opposition to a dispatch of the Self-Defence Forces to the country.

Under its post-war pacifist constitution, Japan is barred from deploying troops overseas for combat, but Defence Minister Toshimi Kitazawa had recently weighed sending military personnel to the region for aid missions.

Japan also said it would implement as quickly as possible a plan to distribute aid worth one billion dollars over two years to neighbouring Pakistan under a package the government pledged in April.

Later in the day, Hatoyama spoke by phone with Afghan President Hamid Karzai and explained the content of the assistance package, a foreign ministry official said.

Karzai thanked Hatoyama for Japan’s support, vowing to fight against corruption and revamp his troubled government by ‘effectively using the assistance to be given by Japan,’ the official said.

Hatoyama was expected to brief Obama about the aid at a summit Friday.

Western governments have poured 20 billion dollars into Afghanistan since late 2001, when the United States led an invasion of the country following the September 11 attacks blamed on Al Qaeda extremists in the country.

Obama has been weighing in recent weeks whether to step up troop deployments in Afghanistan, where widespread irregularities marred the election that has won Karzai another term.

Top US and NATO commander General Stanley McChrystal has asked for some 40,000 extra troops to fight a deadly insurgency by Taleban militants and Al Qaeda-linked groups in Afghanistan.