(Updates to late afternoon)
TORONTO, March 19 (Reuters) - Falling resource shares continued to pull the Toronto Stock Exchange's main index lower on Wednesday afternoon, sending the index down by as much as 300 points in the wake of sagging commodities prices.
The S&P/TSX composite index .GSPTSE was down 258.64 points, or 1.97 percent, at 12,878.06, easing back from a session low of 12,832.38.
The materials sector was the biggest loser on the benchmark, shedding 5 percent, while its smaller subindex of gold producers and miners gave up 3.7 percent and 5.4 percent respectively.
The price of gold was stung by profit-taking after Tuesday's interest rate cut from the U.S. Federal Reserve. Other metals also followed bullion's downward momentum.
The large energy sector was down 3.6 percent, with Suncor Energy (SU.TO) giving up C$4.92, or 4.8 percent, at C$98.00 and Petro-Canada PCA.TO off C$2.77, or 6.1 percent, to C$42.95.
Oil prices were hit by worries that the global demand for energy could be weakened by a slowdown in the United States.
The small telecoms group was down 2.5 percent, while Rogers Communication (RCIb.TO) dipped C$1.30, or 3.7 percent, to C$34.10.
Investors were also rethinking the strong advances the Toronto benchmark saw in the previous session, boosted by the U.S. interest rate cut. Analysts said Tuesday's optimism had been overdone and concerns over more fallout from the credit crunch remained.
Of the benchmark's 10 main sectors, only the financials stayed above water, rising 1.1 percent. Bank of Nova Scotia (BNS.TO) was up 70 Canadian cents, or 1.6 percent, at C$44.86, and Canadian Imperial Bank of Commerce (CM.TO) added 58 Canadian cents, or 1 percent, to C$61.33.
$1=$1.01 Canadian Reporting by Leah Schnurr; editing by Renato Andrade