JAPAN kept its position as the world's largest creditor nation for the 22nd straight year in 2012, government data showed yesterday, as the dollar's gains helped inflate the value of overseas assets.

Tokyo was followed by the Chinese mainland and Germany in third place in the ranking, which reflects the difference between the value of assets held abroad, including foreign debt and property, minus a nation's liabilities, such as foreign purchases of its own debt and domestic assets.

In Japan's case, net overseas assets stood at 296.3 trillion yen at the end of last year, or US$2.9 trillion at yesterday's rate, according to the finance ministry.

The yen has tumbled since Prime Minister Shinzo Abe swept landslide December elections on a pledge to boost the world's third-largest economy with a plan that includes big government spending and aggressive central bank monetary easing, which tends to weigh on the unit.

A weaker yen means that assets denominated in another currency, such as the dollar, would become more valuable when calculated in yen terms.

But analysts said there were no guarantees Japan would retain the title going forward as it faces big trade deficits, fueled by surging dollar-denominated energy imports in the wake of the Fukushima atomic crisis, while carrying a massive public debt.

Abe's pro-spending measures threaten to inflate a debt pile, which at more than twice the size of the economy is the worst among industrialized nations.

"The exchange-rate effect provides only a temporary boost," said Tsuyoshi Nakazawa, foreign investment analyst for Mitsubishi UFJ Morgan Stanley Securities in Tokyo.

"Whether Japan can stay as a major creditor nation will depend on its economic competitiveness and energy consumption pattern ... Japan is living off its legacy right now," Nakazawa told Dow Jones Newswires.

The Chinese mainland's net overseas assets were 150.3 trillion yen last year, followed by Germany with 121.9 trillion yen, Switzerland at 84.7 trillion yen and Hong Kong with 63.4 trillion yen, the Japanese government figures showed.