Sep 23, 2011 (Bloomberg) - Commodities were set for their worst week in more than four months on deepening concern that policy makers are running of tools to avert another global recession, hurting demand for metals, fuel and food.

The Standard & Poor's GSCI Index of 24 commodities gained 0.3 percent by 12:33 p.m. in Seoul, trimming the week's decline to 6.6 percent, the worst since May 6. The gauge is heading for its biggest quarterly loss since 2008. Copper fell to a one-year low and spot gold was set for its worst week in more than four months. Oil was poised for the first weekly drop in five.

"Markets latched onto the downbeat tone," Natalie Robertson, a commodity analyst at Australia & New Zealand Banking Group Ltd., wrote in a report today. "Sentiment is bearish, so we can expect some more selling pressure unless policy circuit breakers are enacted."

Central bankers and finance ministers will discuss the economic outlook today at the annual meetings of the International Monetary Fund and World Bank in Washington. The Federal Reserve on Sept. 21 said it will replace $400 billion of short-term debt with longer-term Treasuries, saying it sees "significant downside risks" to growth.

The world economy will expand 4 percent this year and next, the International Monetary Fund said on Sept. 20, cutting forecasts made in June for a 4.3 percent expansion this year and 4.5 percent in 2012.

Three-month copper on the London Metal Exchange fell as much as 2.2 percent to $7,505 a metric ton, the lowest price since September last year, and traded at $7,580. Prices declined for a sixth day and have slumped 26 percent from the record $10,190 on Feb. 15.

China Manufacturing

Manufacturing in China, the world's largest metals user, may shrink for a third month in September, according to a preliminary index of purchasing managers from HSBC Holdings Plc and Markit Economics released yesterday. The initial reading for this month was 49.4 compared with a final 49.9 for August and 49.3 for July. Figures below 50 signal a contraction.

Goldman Sachs Group Inc. yesterday said investors should keep buying commodities because "supply disappointments" will support prices even as the sovereign-debt crisis and slowing economies threaten demand.

Immediate-delivery gold was 0.2 percent higher at $1,743.18 an ounce after yesterday dropping to a four-week low. Spot silver rose 1 percent after falling by the most in more than four months yesterday. Gold for December delivery gained 0.2 percent to $1,745.80 an ounce on the Comex in New York.

November-delivery oil gained 0.8 percent to $81.19 a barrel on the New York Mercantile Exchange. The price yesterday fell to the lowest for a most-active contract since Aug. 9. Wheat for December delivery increased 1.7 percent to $6.4425 a bushel on the Chicago Board of Trade, trimming this week's loss to 6.4 percent.