TOKYO (AFP) - The Bank of Japan on Friday said its board voted unanimously to keep its key rate unchanged between zero and 0.1 percent as it continued with earlier measures to help safeguard Japan's fragile recovery. The BoJ maintained its 50 trillion yen ($650 billion) scheme to buy securities and boost liquidity to help shore up confidence amid worries over the strong yen and the health of the global economy. It also extended by six months a 1.0 trillion yen loan programme for financial institutions in areas affected by the March 11 earthquake, up to the end of April 2012, in a bid to support rebuilding efforts. "Japan's economic activity has continued picking up," the BoJ said in a statement, a more optimistic view of a recession-hit economy that saw output tumble in the aftermath of the March disasters. Japan's manufacturers have staged a rebound since the March 11 earthquake and tsunami that left around 20,000 dead or missing and shattered crucial supply chains, heavily disrupting Japanese industry. But concerns have grown that those efforts could be undermined by a strong yen, which erodes exporters' profits, makes domestically-made goods more costly to sell overseas and prompted fears more firms will shift production abroad. "Production and exports have continued to increase, although their paces have moderated after going through the recovery phase immediately following the quake-induced plunge," the BoJ said. Output rose by less than forecast in August. But the BoJ warned the pace of overseas growth "is expected to slow for the time being" and the consequences of sovereign debt problems in Europe and economic weakness in the United States "continue to warrant attention." The Bank of Japan's closely watched Tankan survey showed that sentiment among the country's major manufacturers turned positive in Sept. ember as firms continued their recovery from the impact of the country's March disasters. But while the reading returned to positive levels for the first time since the earthquake, tsunami and the beginning of the subsequent nuclear crisis, it remained below pre-disaster figures. Many economists expect the BoJ to mull further easing steps by expanding its asset-buying programme in coming months if the yen surges to a fresh record high against the dollar and Europe's debt crisis deepens. In August the BoJ expanded its scheme to buy securities and boost liquidity to 50 trillion yen amid worries over the strong yen, in tandem with a government market intervention in a bid to weaken the unit. The bank's asset purchase fund, a key policy tool it uses to buy Japanese government bonds, corporate bonds and exchange traded funds, was expanded to 15 trillion yen from 10 trillion yen. It also boosted a credit facility by five trillion yen to 35 trillion. But the safe-haven yen nevertheless hit a post-war high against the dollar in August and this week struck a 10-year high against the beleaguered euro. Japan has unveiled a plan to make $100 billion available to help companies acquire assets overseas while boosting its oversight of foreign exchange markets against speculative moves. In the aftermath of the earthquake, the BoJ injected a record amount of cash into the banking system. It has also set up the lending scheme for banks in quake-hit areas to ensure financial institutions in disaster-hit areas can meet demand for post-quake reconstruction funds.