By Tetsushi Kajimoto

TOKYO (Reuters) - Japan's exports fell for a 12th straight month in September from a year earlier, official data showed, as the yen's gains undermined export prices, but rising shipment volumes pointed to a tentative pick-up in global demand.

Ministry of Finance data issued on Monday showed Japan's exports fell 6.9 percent in September from a year earlier, following a 9.6 percent decline in August, dragged down by U.S.-bound shipments of cars, China-bound shipments of electronics parts and exports of steel.

The result is a little less gloomy than the median forecast in a Reuters poll of economists for a 10.4 percent fall as the yen's 16 percent gains versus the dollar from a year earlier hurt the value of exports.

In terms of volume, exports rose 4.7 percent in the year to September, the fastest gain in nearly two years and rising for a second straight month, the data showed.

"It's a positive sign that export volume grew after having been more or less flat until recently," said Hidenobu Tokuda, senior economist at Mizuho Research Institute.

Analysts say net exports probably contributed to Japan's July-September GDP expansion, reflecting declines in imports, although weak overseas demand shaved 0.3 percentage points off second-quarter growth.

Asian demand for iPhone-related electronics parts, and car sales in Europe recovering from a slump caused by the euro zone debt crisis, helped increase Japanese export volumes.

While these possibly temporary factors may help boost sales in the short run, the Japanese export engine would still lack strength given lackluster capital spending around the world, Tokuda said.

In a further positive sign, Japanese manufacturing activity grew at the fastest pace in nine months as new orders rose, with the Flash Markit/Nikkei Japan Manufacturing Purchasing Managers Index (PMI) rising to a seasonally adjusted 51.7 in October.

New data will be closely scrutinized by the Bank of Japan at its Oct. 31-Nov. 1 policy meeting, where it issues new economic and price forecasts. The central bank is expected to hold off from expanding stimulus after having just revamped its policy framework last month, sources say.

By destination, the MOF data showed the value of exports to China - Japan's largest trading partner - fell 10.6 percent in September from a year earlier, marking the seventh straight month of annual declines.

Shipments to Asia, which accounts for more than half of Japanese exports, fell 8.4 percent, posting the 13th straight month of falls.

U.S.-bound exports fell 8.7 percent, posting a seventh straight declining month, while exports to the European Union rose 0.7 percent, the first increase in five months.

(Reporting by Tetsushi Kajimoto; Editing by Chris Gallagher and Eric Meijer)