MELBOURNE - The Australian share market closed weaker amid lower commodity prices and a mixed US lead.

The Reserve Bank of Australia's (RBA) decision to leave the official cash rate unchanged was widely expected and had little effect on the equities market.

At 1615 AEST, the benchmark S&P/ASX200 index was 16.8 points lower, or 0.44 per cent, at 3,766.9, while the broader All Ordinaries index eased 16.4 points, or 0.43 per cent, to 3,767.8 points.

On the Sydney Futures Exchange, the September share price index contract was 15 points lower at 3,734 points on a volume of 19,141 contracts.

The RBA's no-change decision was widely expected and the futures market had priced in only a four per cent chance of a rate cut, IG Markets analyst Ben Potter said.

"The real focus was on what they were going to say and if they were going to dull down the sense that people think there was going to be a rate rise before year's end, which is what they've tried to do.

"The bias is certainly towards an easing if need be down the track."

Mr Potter said trading was "defensive", with utilities and telcos leading the market.

Major movers included AGL Energy, up 63 cents, or 4.79 per cent, at $13.78, and Telstra, which advanced three cents, or 0.91 per cent, to $3.32.

Strength in staples saw Wesfarmers add 24 cents, or 1.05 per cent, to $23.02, Mr Potter said.

Energy and materials stocks weighed down the market, with Rio Tinto losing $1.15 or 2.37 per cent to $47.35 and BHP Billiton down 37 cents, or 1.13 per cent, to $32.25.

By 1620 AEST oil stocks lost ground, with Oil Search down three cents at $5.29, Santos dropping 33 cents to $13.23 and Woodside Petroleum 38 cents weaker at $40.47.

Major gold stocks moved into negative territory along with the gold price.

Lihir Gold gave up two cents at $2.85, Newcrest Mining fell 61 cents to $29.57 and dual-listed Newmont Mining eased six cents to $4.96.

At 1628 AEST the spot price of gold in Sydney was US$923.50 per fine ounce, down US$3.45 on Monday's close of US$926.95.

China-focused gold miner Sino Gold Mining made its debut on the ASX 100 index on Tuesday and finished 27 cents, or 5.78 per cent, higher at $4.94.

Origin Energy eased two cents to $13.80 after signing a new agreement with tax authorities to minimise the company's compliance costs.

The financials sector was mostly weaker, with Westpac the only big four bank to make a gain.

Westpac added two cents to $19.10, Commonwealth Bank eased six cents to $36.99, National Austalia Bank fell 16 cents to $21.67 and ANZ Banking Group lost eight cents to $15.90.

QBE Insurance was a rare bright spot in the sector, gaining 25 cents to $19.57.

By 1634 AEST retailers were mixed, with clothing retailer Country Road surging 15 cents, or 4.84 per cent, to $3.25, grocer giant Woolworths four cents weaker at $26.27 and upmarket store owner David Jones up four cents to $4.41.

But major media stocks fell into negative territory.

Consolidated Media gave up three cents to $2.21, Fairfax Media lost two cents to $1.105 and its rival News Corporation dropped 34 cents to $12.35.

News' non-voting scrip fell 16 cents to $10.80.

Making news today, ABB Grain Ltd lost 25 cents, or 2.67 per cent, to $9.10 after it downgraded its 2009 full year underlying profit guidance, blaming slowing consumption of beer in Asia and a reluctance of Australian farmers to buy fertiliser and merchandise to grow crops.

Online bookmaker Centrebet International Ltd gained 3.5 cents to 93.5 cents after announcing it expected strong profit growth in fiscal 2010, after upgrading guidance for the current year.

The top traded stock by volume was Lakes Oil NL, with 170 million shares changing hands for $2.29 million and pushing the share price 0.1 cents, or 7.14 per cent, higher at 1.5 cents.

Preliminary national turnover reached 1.63 billion shares, traded for a value of $3.57 billion, with 409 stocks up, 559 down and 296 steady.