BHP Billiton has adopted one of the most ambitious gender targets of any large company by pledging to make half its workforce women in just nine years, with chief executive Andrew Mackenzie saying diversity will improve performance at the resources giant.

At BHP's annual meeting in London on Thursday Mr Mackenzie will announce an "aspirational goal" for gender balance by 2025 at the Melbourne-based mining and energy group where women currently make up 17 per cent of the global workforce.