BHP has been accused of using impossibly high potash prices to justify the economics of its $US5.7 billion ($8.3 billion) Jansen potash project, with big potash producers warning they can bring idled production or mine expansions into the market faster and cheaper than BHP can build Jansen.

Revised plans for the Jansen project published by BHP last week suggest the first phase of the Canadian project will produce about 10 per cent more potash each year than previously planned and cost about 10 per cent more to build at between $US5.3 billion and $US5.7 billion.