BHP Billiton chief executive Marius Kloppers says there are signs of a pullback in demand for iron ore as China finishes rebuilding its inventories of raw materials.

Addressing the company's annual general meeting in London, Mr Kloppers says China was the major - and sometimes only - source of demand for commodities in the second half of the year.

"We as a company do believe that there's been a substantial inventory build in China," he said.

"So that's our view - that restocking in China is essentially complete, but we're seeing some signs of pullback as a consequence."

Mr Kloppers also says steel output is climbing in the US and Europe, providing the first signs of restocking in the major economies.