Global miner BHP Billiton on Wednesday announced a 34.8 percent dive in annual net profit to $15.42 billion and delayed a key project, citing weakness in commodity prices and cost pressures.

The world's biggest miner said it would put off expansion of its massive Olympic Dam project in Australia after a 15 percent plunge in underlying earnings due to softer prices for most of its products through 2012.

It is a significant reversal of fortunes for the company following a record US$23.6 billion profit last year -- the largest figure ever recorded in Australia's corporate history.

Though BHP achieved record annual production at 10 of its operations including its flagship west Australia iron ore business, slowing global growth and uncertainty over the outlook hit commodity prices, undercutting profit.

"Concerns surrounding the stability of the Eurozone and the decline in economic activity that accompanied the managed slowdown of growth in China led to significan market volatility in the 2012 financial year," BHP said.

"In the short term, we expect volatility in commodity markets to persist as temporary weakness in the manufacturing and construction sectors across all key markets is expected to weigh on market sentiment."

In the medium term BHP said it expected a "measured improvement in the external environment" beginning in the first half of the 2013 financial year, driven particularly by growth in China.

BHP said it had been "quick to respond" to the weaker operating conditions, closing energy-intensive silicomanganese alloy production in South Africa and temporarily shutting a manganese smelter and coal mine in Australia.

"The viability of other high-cost operations is being assessed and additional measures are being implemented that will substantially reduce operating costs and non-essential expenditure across the business," the Anglo-Australian miner said.

The profit figure was weighed by writedowns from BHP's US shale gas and Australian nickel assets and US$342 million in charges related to the suspension or early closure of operations and the Olympic dam delay.

BHP warned of job losses at its Australian operations earlier this month due to sagging Chinese demand and the ongoing turbulence in Europe, but there were no references to jobs in the results data.