Iron ore miner Fortescue Metals Group's first half profit has dropped 40 per cent because of weaker ore prices.

But the company says it has had a strong start to the second half of the 2012/13 financial year with iron ore prices returning to high levels and cost savings being realised.

Fortescue made a net profit $US478 million ($A463.99 million) in the six months to December 31, down from $US801 million in the previous corresponding period.

It will not be paying shareholders an interim dividend, and said it would review its dividends after its full year result is announced.