The world's biggest resources company said today it had an attributable profit in the six months to December 31 of $US6.135 billion ($6.99 billion), up from $US2.617 billion ($2.98 billion) in the prior corresponding half.

Excluding exceptional items, BHP posted attributable profit of $US5.702 billion ($6.5 billion), down seven per cent from $US6.128 billion ($6.98 billion) in the first half of 2008/09.

The company's underlying earnings before interest and tax (EBIT) were $US8.5 billion ($9.68 billion) for the first six months of the financial year, down from $US11.9 billion ($13.76 billion) in the corresponding period of 2008/09.

Analysts had tipped underlying EBIT to be $US7.9 billion ($9.14 billion).

Analysts had also tipped an attributable profit pre-exceptional items of $US5.1 billion ($5.81 billion).

BHP Billiton said strong sales volume growth on the back of demand recovery, particularly in iron ore, metallurgical coal and manganese, and good cost controls had helped partially offset the negative impacts of lower prices.

But the fall in commodity prices and a weak US dollar had adversely impacted earnings compared to the prior period.

It declared an interim dividend of 42 US cents per share, compared to 41 US cents for the prior corresponding period.

BHP Billiton said global economic conditions hadimproved over the past six months, as the United States and Europe lifted industrial output from previously depressed levels and China returned to double digit growth.

"Government stimulus measures appear to have supported the restocking activities in the developed economies and a gradual return to normalised global trade," it said.

But the company remains cautious about the speed and strength of the global economic recovery across the developed world.

"It appears that stimulus measures that supported the recovery have not fully addressed structural issues such as weak labour markets and excess production capacity in developed economies," it said.

The company said a further variable would be the impact of any measures to control loan growth in China.

"It is evident that in the short term, the Chinese government will focus on containing asset inflation,'' it said.

BHP said commodity markets will continue to be largely dependent on Chinese and Indian demand.

"Real commodity demand in the developed economies remains restrained and the impact of the gradual withdrawal of government stimulus will be a key driver," it said.

"In the long term we continue to expect strong growth in demand for our commodities."

The company said any effects on commodity demand due to potential weakness in developed countries was likely to be offset over time by continuing growth from China and India.

"However, with reduced capital investment in new mining capacity since 2007, supply may struggle to keep pace with demand in the medium and longer term," the company said.