Japan's trade deficit in September surged 64.1 percent from a year earlier, extending its string of shortfalls to a record 15th consecutive month.

A weaker yen has been helping Japan's export picture, but the volume of shipments was down last month while the country's energy bill remained high due to imports of pricey fossil fuels.

Energy imports surged after the 2011 Fukushima crisis forced the shutdown of Japan's nuclear reactors.

On Monday, the finance ministry said Japan recorded a trade deficit of 932.1 billion yen ($9.5 billion), well above a 568.2 billion yen deficit in the year earlier.

That was the 15th straight month of deficits, the longest spell since comparable data started in 1979.

The value of exports rose 11.5 percent to 5.97 trillion yen while imports jumped 16.5 percent to 6.90 trillion yen.

By volume, exports were down 1.9 percent while imports slipped 2.2 percent, with the dollar up an average of 25 percent on the yen in September from a year ago, the ministry said.

The yen depreciated rapidly since late last year as Prime Minister Shinzo Abe's economy stimulus plan -- including massive central bank monetary easing -- helped push down the unit.

A weaker yen boosts competitiveness and profitability among Japanese exporters but it also pushes up import costs. (AFP)