* Softer dollar fails to support prices
* Copper slides towards lowest in a week
* Coming up: Fed policy statement at 1800 GMT (Updates prices)
By A. Ananthalakshmi
SINGAPORE, April 27 (Reuters) - Copper slid for a third straight session on Wednesday as worries over demand in top consumer China outweighed support from a softer dollar.
Three-month copper on the London Metal Exchange fell 0.5 percent to $4,935 a tonne by 0713 GMT, edging close to a one-week low of $4,916.50 reached on Tuesday.
The most-traded copper contract on the Shanghai Futures Exchange closed 0.5 percent lower at 37,630 yuan ($5,797.62) a tonne, extending a 1.3 percent decline overnight.
“The weaker dollar failed to support base metals as investors continued to liquidate positions after the strong run last week,” ANZ said in a note.
“Copper led the declines as worries over rising inventories continued. The strong performance of Chinese steel markets has rubbed off on aluminium, with volumes on the Shanghai Futures Exchange hitting a record high,” it said.
Chinese commodities exchanges stepped up efforts on Tuesday to curb surging prices in response to last week’s spike in prices and volumes, which some analysts said were not matched by fundamentals for the underlying commodities.
Analysts say the spike was largely due to speculators betting that a rise in infrastructure spending in China would lift raw material prices, which have been battered for years by a broad-based glut.
London aluminium climbed to an eight-month high last week, while copper rose to its highest level in a month.
The concerns over China offset the impact of a softer dollar, which fell for a third day against a basket of major currencies as investors believed disappointing U.S. factory and consumer confidence data would prompt the Federal Reserve to be cautious about raising interest rates.
The U.S. central bank kicked off a two-day policy meet on Tuesday and is due to issue a statement at 1800 GMT.
The Fed is likely to keep rates steady, but investors’ focus rests squarely on the tone of its statement. A dovish Fed could weaken the greenback and support commodities priced in dollars.
Elsewhere, global nickel demand will slightly outpace supply this year, the International Nickel Study Group said, ending four years of surplus.
Output of nickel - used to make stainless steel - will drop to 1.913 million tonnes in 2016, although consumption will increase to 1.962 million tonnes, it said.
Three month LME copper
Most active ShFE copper
Three month LME aluminium
Most active ShFE aluminium
Three month LME zinc
Most active ShFE zinc
Three month LME lead
Most active ShFE lead
Three month LME nickel
Most active ShFE nickel
Three month LME tin
Most active ShFE tin ($1 = 6.4906 Chinese yuan) (Reporting by A. Ananthalakshmi; Editing by Richard Pullin and Sunil Nair)