Prices of iron ore, the key ingredient in steel, will average $150 per metric tonne from 2012 to 2015, research and investing company Goldman Sachs & Partners Australia Pty Ltd said.

From an earlier $140 per metric tonne estimate, Goldman Sachs & Partners Australia Pty Ltd raised its forecast based on expectations that Brazil's output of the raw commodity will slide "lower than expected" in 2012.

Brazil is the world's second-biggest exporter of iron ore, next to Australia.

The "substantial delays" in the implementation of new projects as well as expansions on existing facilities in Brazil will lead the country's exports of iron ore to fall by 150 million tonnes to 447 million tonnes in 2012, Goldman Sachs & Partners Australia Pty Ltd said.

Iron ore for delivery dropped 1.8 per cent to $134.80 a tonne on Wednesday, according to The Steel Index.

Goldman Sachs & Partners Australia Pty Ltd also raised its 2013 forecast of iron ore prices by 38 per cent to $165 a tonne, 50 per cent to $150 a tonne by 2014 and 60 per cent to $120 a tonne by 2015.

Shortage of iron ore will remain in 2012 and 2013 before it adjusts to a "modest notional surplus" the following year, the research and investing company said.