West Australian mining magnate Gina Rinehart is on the cusp of sending her first iron ore shipment to Asia.

The bulk carrier, MV Anangel Explorer, docked late yesterday at the newly completed Roy Hill wharf in Port Hedland and is being loaded.

"This is a truly momentous occasion," Mrs Rinehart said in a statement issued to media.

"To paraphrase the great Sir Winston Churchill, may I say to the employees of Hancock Prospecting and Roy Hill, the light of history shall shine on all your hard hats, and the first Roy Hill ship," Mrs Rinehart was quoted as saying in the media statement.

However, the project milestone comes after significant delays at Roy Hill and amid a tough resources market.

Head of commodities research at ANZ, Mark Pervan, described the timing as 'unfortunate' and said the additional iron ore would do nothing to improve prices.

"The market is in a pretty depressed state," Mr Pervan said.

Rural news in your inbox? Subscribe for the national headlines of the day.

"There is a fair bit of focus on the oversupply of iron ore in the market at the moment, so this only adds to those concerns."

The iron spot price plunged during the month of November, opening this morning at $US42.97 a tonne.

Mr Pervan said he expected the producers who would most feel the squeeze from Roy Hill's impending entry into the market were in China.

"I think the ones who will feel the pinch the most are the Chinese domestic iron ore suppliers," he said.

"They are already under a lot of pressure because their costs are much higher."

Roy Hill's first shipment of iron ore is expected to set sail later this week.