TOKYO - The Bank of Japan (BOJ) on Wednesday left its key short-term interest rate unchanged at virtually zero and maintained the size of its asset purchasing program as a means to facilitate economic growth in Japan.

The central bank said that governor Masaaki Shirakawa and his nine-member policy board voted unanimously to keep the overnight call rate target between 0 and 0.1 percent, in a widely expected move.

The bank maintained that no monetary policy changes would take place pending prices showing more "medium-to long-term" stability, according to the central bank's statement.

The board also all agreed that the bank's asset-buying fund should remain unchanged at 20 trillion yen ($260 billion) and its funding program for commercial banks held constant.

"The pick-up in Japan's economic activity has paused, mainly due to the effects of a slowdown in overseas economies and of the appreciation of the yen," the BOJ said in a statement.

The statement followed the results of a two-day policy board meeting and the assessment of Japan's economy was downgraded from the previous month's which stated that Japan's economy had "continued picking up, but at a more moderate pace."

The latest assessment by the BOJ marks the second straight monthly downgrade by the bank on Japan's economy.

The central bank also added that the flooding in Thailand had added downward pressure to some industries, including Japan's key automobile and electronic manufacturing sectors and that Japan was not immune from Europe's sovereign debt woes.

Japanese exports fell 4.5 percent in November from a year earlier, marking the second straight month of decline, government data showed prior to the release of the BOJ's latest report Wednesday

Japan's trade deficit widened to 684.7 billion yen (8.79 billion U.S. dollars) from 273.8 billion yen in October, above consensus forecasts for a deficit of 440 billion yen, the government said.

The government also noted that exports plummeted at the fastest pace in six months due to a persistently strong yen, eurozone sovereign debt woes and economic malaise in emerging economies.

But imports rose 11.4 percent, meanwhile, totaling 5882.4 billion yen in the recording period, the government said.

Japan's key export sector has been adversely affected by a persistently strong yen that has spiked to record post-WW II highs, as in times of economic uncertainty investors view the Japanese currency as a safe haven, while short-term speculators look to the yen to pocket quick FX profits, driving up the currency in money markets versus its major counterparts.

However, regarding domestic demand the BOJ struck a more positive tune saying that a modest uptick had been noticed.

"As for domestic demand, business fixed investment has been on a moderate increasing trend and private consumption has remained firm," the central bank's statement said.

Japan's latest GDP figures showed the economy had grown following the march earthquake-induced rescission, but economists predict growth will slow as production and reconstruction related operations start to decline following massive rebuilding efforts in the weeks and months following the monumental disaster, which struck on March 11 with the quake and ensuing tsunami leveling many areas along Japan's eastern seaboard.

The central bank last eased policy in October by increasing the size of its asset purchasing scheme to counter fallout from the yen's sharp appreciation against other major currencies and along with government initiatives has endeavored to help try to ease the impact on Japan's key exports sector, while encouraging commercial banks to lend to each other. ?

The central bank said that it expects the economy here to remain flat for the time being and the finance ministry said it will continue to lean on the BOJ to unroll additional easing measures in a bid to defend against a potentially shrinking economy and speculative currency attacks..

Bank of Japan governor Masaaki Shirakawa is scheduled to give a news conference later in the day.