A summary of trading in key commodities markets overseas:
US crude oil prices have risen for the first time in five days, while Brent has dropped amid worries about global supplies ahead of the weekly US petroleum inventories report.
US benchmark West Texas Intermediate (WTI) for September delivery rose 59 cents to $US47.98 on the New York Mercantile Exchange on Tuesday.
Brent North Sea crude for delivery in September closed at $US53.30 a barrel in London trade, slipping 17 cents from Monday's settlement in a fifth day in a row of declines.
Gold has firmed but remains near five-and-a-half-year lows as markets brace for this week's Federal Reserve meeting, at which policymakers are expected to give further clues on the timing of a US rate increase.
The Fed suggested earlier this year that a near-term rate rise was on the cards if economic data supported such a move, but slowing growth in China and a drop in commodity prices have led some to question whether it will be pushed back.
Spot gold was up 0.2 per cent at $US1,095.28 an ounce at 2.26 pm EDT (0426 Wednesday AEST), not far from Friday's low of $US1,077, its weakest since early 2010.
US gold futures for August delivery settled down US20 cents an ounce at $US1,096.40.
Spot platinum was up 0.1 per cent at $US980.25 an ounce, near last week's six-and-a-half-year low.
Silver was up 0.9 per cent at $US14.67 an ounce and palladium was up 0.9 per cent at $US617.50 an ounce.
Copper prices have risen, but the market remains nervous over the latest convulsions in Chinese equities and the possible ramifications for demand from the world's top metals consumer.
Benchmark copper on the London Metal Exchange rose 2.2 per cent to close at $US5,300 a tonne from $US5,188 at the close on Monday, when the metal used in power and construction hit a six-year low at $US5,164.
Three-month aluminium gained 1.0 per cent to close at $US1,655, nickel gained 3.00 per cent to close at $US11,325 , lead rose 1.6 per cent to close at $US1,722.50 and zinc rose 2.4 per cent to close at $US1,980.
Tin rose 3.2 per cent to close at $US16,150, matching its May 7 high on expectations of falling shipments from top exporter Indonesia from August 1.