Rio Tinto is investing $676m in early works and procurement at the Pilbara region of Western Australia, to speed up its iron ore expansion programme.

With this investment, the firm will raise its iron capacity to 333Mtpa in the first half of 2015, six months earlier than planned.

The amount will be used for early rail and port engineering works, which will include the assembly of additional construction accommodation, the continuation of dredging, marine works and stockyard earth works contractors, and the procurement of key equipment.

The rail-related funding will enable early engineering and accelerated procurement of long-lead items such as rail plant.