SYDNEY- The Australian share market posted a third successive day of strong gains, buoyed by energy and banking stocks, and a positive lead from offshore bourses.

At the 1615 AEST close, the benchmark S&P/ASX200 index was up 71.1 points, or 1.81 per cent, at 3,995.6, after trading as high at 4022.3.

The broader All Ordinaries gained 70.3 points, or 1.79 per cent, to 3,987.8 points.

On the Sydney Futures Exchange, the September share price index contract was 83 points higher at 3,971 on 29,598 contracts.

IG Markets research analyst Ben Potter said the share market rose after investor sentiment was boosted by Wall Street's strong performance.

"However, after three strong sessions, traders are beginning to take some profits off the table," he said.

Mr Potter said he expected downbeat corporate news from the US to pull back the market a little.

Mr Potter said data showing China's economy had expanded at an increased rate was largely factored into the markets.

China's economy expanded by 7.9 per cent from a year earlier, official data showed on Thursday.

Among local energy stocks, Woodside rose 51 cents to $41.40, Santos increased 35 cents to $13.92, and Oil Search grew 13 cents to $5.41.

Among the banks, Commonwealth Bank gained 59 cents to $39.41, ANZ lifted 15 cents to $16.65, and Westpac rose 22 cents to $20.18.

NAB was up 60 cents at $23.95. It announced on Thursday that subsidiary Bank of NZ had lost a court case that could cost it around A$530 million in tax and interest.

Former St George Bank chief executive Paul Fegan has been appointed to the board of AMP.

AMP lifted 11 cents, or 2.29 per cent, to $4.91.

The major miners were stronger. Rio Tinto shares gained $2.32, or 4.63 per cent, to $52.40, while rival BHP Billiton lifted 61 cents, or 1.78 per cent, to $34.91.

Among the gold miners, Newmont was up 16 cents at $5.04, Newcrest rose 74 cents to $31.00 and Lihir Gold added three cents to $2.92.

Sino Gold, which announced on Thursday a 51 per cent increase in gold production in the June quarter, gained 23 cents to $5.23.

The spot price of gold in Sydney was US$937.00 per fine ounce at 1626 AEST, up US$8.55 on Wednesday's close of US$928.45.

Retailers were stronger. Coles owner Wesfarmers gained 52 cents to $23.50, Woolworths grew 59 cents to $27.42, and David Jones rose 11 cents to $4.68.

Telstra shares were down two cents at $3.40, while rival Optus owner Singapore Telecommunications added five cents to $2.82.

Qantas lifted seven cents to $2.04 and Virgin Blue gained 0.5 cents to 30 cents.

In the US, Wall Street gained on robust company results and an improved economic outlook from the Federal Reserve.

The Dow Jones industrial average closed up 256.72 points, or 3.07 per cent, at 8616.21.

Making news, toll roads operator Macquarie Infrastructure Group (MIG) said the value of its assets was likely to have fallen by almost $2 billion in the second half of 2008/09 due to lower traffic volumes and adverse currency movements.

MIG securities were up 2.5 cents at $1.425.

Seven Network on Wednesday lifted its stake in Consolidated Media Holdings to the maximum level allowed before launching a takeover - at 19.9 per cent.

Seven dropped five cents to $5.67 and Consolidated Media added five cents to $2.69.

Fairfax lifted three cents to $1.215, Ten Network added one cent to $1.14, News Corp gained 33 cents to $13.17 and its non-voting scrip also lifted 33 cents, to $11.28.

The top-traded stock by volume was Lakes Oil NL, with 198.96 million shares worth $2.4 million changing hands.

Its shares were down 0.3 cents, or 21.43 per cent, at 1.1 cent.

Preliminary total turnover reached 2.21 billion shares worth $5.31 billion, with 759 stocks up, 278 down and 311 unchanged.