Arrium shipped a record amount of iron ore in the first quarter of the financial year, but was forced to cut prices for customers.

The miner, formerly known as OneSteel, shipped 3.45 million tonnes of iron ore in the September quarter, up by 0.29Mt on the previous quarter.

However, the average realised price for the mineral fell by $US12 to $US73 a tonne.

Arrium, along with other iron ore miners, has been struggling with falling iron ore prices in 2014 amid a slide in demand from China.

The miner in September tapped investors for more than $750 million to help pay down its $1.7 billion in debt.

Shares in Arrium were 1.25 cents higher at 34.75 cents at 1031 AEDT.