The Australian share market is trading firmer as BHP Billiton’s half-year production results exceed expectations and inflation figures come in below expectations.

At 1200 AEDT on Wednesday, the benchmark S&P/ASX200 index had risen 15.2 points, or 0.32 per cent, to 4,794.3 points, and the broader All Ordinaries index had added 14.5 points, or 0.3 per cent, to 4,817.4 points.

The S&P/ASX200 index reached a fresh 20-month high when it touched 4802.1 at 1029 AEDT, the highest level since May 2, 2011.

On the ASX 24, the March share price index futures contract was up 21 points at 4,753 points, with 12,078 contracts traded.

The Australian market reached its morning high after mining giant BHP Billiton’s half-year production results exceeded expectations.

Bell Potter senior adviser Stuart Smith said that with almost four million shares being traded in the company on Wednesday, the results were spurring the Australian equities market.

“I can see BHP travelling ahead from here,” he told AAP.

BHP Billiton said its West Australian operations produced 81.96 million tonnes of iron ore in the six months to December 31, up two per cent on the same period in 2011.

In the three months to December, iron ore production totalled 42.19 million tonnes, up three per cent. Analysts had forecast a flat result.

The company maintained its full-year iron ore production forecast at 183 million tonnes.

BHP Billiton shares rose 42.5 cents, or 1.16 per cent, to $37.00.

But fellow miner Fortescue lost 1.5 cents, or 0.32 per cent, to hit $4.62 while Rio Tinto fell 15 cents, or 0.22 per cent, to $66.74.

Investors appeared less excited by the release of inflation data showing the consumer price index (CPI) rising by 0.2 per cent in the December quarter, which was below market expectations of a 0.5 per cent increase.

The CPI rose by an annual pace of 2.2 per cent, which was below economists’ expectations of a 2.5 per cent rise.

Mr Smith said the result did little to change market expectations of a near-term interest rate cut.

“We’ll get a rate cut, whether it’s February or March,” he said.

Meanwhile, building products maker Boral has upgraded its forecast for its underlying first-half profit due to cost saving measures and improved trading conditions in the lead-up to Christmas.

Boral now expects its net profit for the six months to December 31, excluding one-off items, to be about $52 million.

At 1202 AEDT, national turnover was 676.2 million securities worth $1.301 billion, with 396 stocks up, 358 down and 288 unchanged.