Rail and infrastructure giant Aurizon has pushed back the deadlines for its part of the West Pilbara Iron ore Project, as the plunge in the iron ore price raises questions about the project's viability.

Aurizon said on Monday morning that following recent discussions with the other partners in the project – Baosteel Resources and its subsidiary Aquila Resources, Korean steel giant POSCO and AMCI – it remains committed to the technical and commercial feasibility study stage for the project, with a the deadline decision on whether to proceed likely in late calendar 2016.

But Aurizon's period of exclusivity to develop an infrastructure solution for the project has been extended until April 30, 2016 and the deadline for Aurizon to provide an "indicative and non-binding" port and rail tariff for the project has been pushed back a month to November 30.

Aurizon said the project participants were "mindful of the volatility in the iron ore markets price" and "have therefore matde an in-principal decison that further project governance measures, in the form of assessment stage gates, be implemented to allow for 'whole of project (mine and infrastructure) oversight and program management".

Iron ore for delivery to the Chinese port of Qingdao last traded at $US61.40 a tonne. The ore price has gyrated in recent months, gaining 31 per cent in the past six weeks from an April 2 low of $US47 a tonne; however, it is still 41 per cent lower than it was a year ago when iron ore traded at $US104 a tonne.