Iron ore is likely to extend its declines in 2015 as global supply exceeds demand and the world's largest producers plan to add production, according to INTL FCStone Inc, which described last year's rout as incredible.

The ferrous sector remains chronically oversupplied and further weakness in iron ore prices is expected over the year, analysts including Edward Meir and Spencer Johnson wrote in a report on the outlook for commodities and currencies.

While there may be a climb of $5 to $7 a metric ton in the early part of 2015, there's no good news for bulls amid the glut, according to the report.