Oslo - Norwegian aluminium group Norsk Hydro's share price fell 10 per cent Monday after the group said it expected a drop in second-quarter earnings.

The company said it expected to report pre-tax profits of some 1.6 billion kroner (316 million dollars), compared to first-quarter earnings of 2 billion kroner.

Second-quarter results were due July 22, the group said.

Hydro said it was "experiencing significant cost increases in the Aluminium Metal business area," adding that "cost increases are mainly related to alumina prices, alumina freight, petroleum coke and other costs."

A week ago, Hydro's share price gained on reports that China was to cut its aluminium production.

Last year, Hydro combined its gas and oil business with Norwegian rival Statoil to focus on its aluminium and power generation activities. (dpa)