The Australian sharemarket was lower at noon as resource stocks dragged the local bourse lower after commodity prices declined.

At 1200 AEDT, the benchmark S&P/ASX200 index had fallen 18.9 points, or 0.54 per cent, to 3,449.2, while the broader All Ordinaries was also down 18.9 points, or 0.54 per cent, at 3,513.7.

On the Sydney Futures Exchange, the December share price index contract was down 15 points at 3,526 on a volume of 13,285 contracts.

Macquarie Private Wealth adviser Helen Spencer said resource stocks led the market lower after commodity prices fell on Thursday.

Oil prices fell $US3.12 to $US43.67 in New York, the lowest in almost four years, due to growing concern about demand in the world's biggest energy consuming nation, the United States.

Copper, the benchmark industrial metal, lost 8.5 cents to $US1.4695 in New York.

"Commodities are now seeing the brunt of the economic slowdown," Ms Spencer said.

"We now have the combination of lower commodity prices and debt refinancing for a lot of resource companies, including Rio Tinto.

"Any level of short term refinancing causes uncertainty, and investors have a huge distaste for uncertainty right now."

Rio shares slumped $2.17, or 6.68 per cent, to $30.33 and BHP Billiton shares lost $1.41, or 5.13 per cent, to $26.09.

Fortescue Metals slumped after the iron ore miner said it had suspended contracts on about two-thirds of its ore shipments, in an effort to switch to greater reliance on deals that require the buyer to freight the product.

Fortescue shares dropped 19 cents, or 7.72 per cent, to $2.27.