BHP Billiton says the hedge fund Elliott Associates' plan to collapse the dual-listed company structure would cost $US1.3 billion ($1.7 billion) to execute before wasting billions worth of franking credits by distributing them to people who cannot use them.

In a detailed presentation into why BHP has rejected the changes proposed by Elliott chief executive Andrew Mackenzie said Australian and South African shareholders had the most to lose. The petroleum division, which Elliott has urged be hived off into a New York-listed company, was a crucial part of the diversification that made the company strong, he added.