Oslo - Norwegian aluminium group Norsk Hydro Wednesday said it was to write down assets worth 3.5 billion kroner (520 million dollars), citing "deteriorating market conditions and high input costs."

The cost was to impact the group's fourth-quarter 2008 results, which were due to be published February 18, the group said.

The group was also to reduce production.

Planned measures including cutting primary aluminium production by 10 per cent or 170,000 tons a year by closing a unit in Norway and reducing capacity at two smelters in Norway and Germany.

Production of remelted aluminum was to be almost halved, corresponding to some 500,000 tons a year, the group said.

In October 2007, Norsk Hydro combined its gas and oil business with Norwegian rival Statoil to focus on aluminium and power generation activities.

Norsk Hydro has about 23,000 employees and activities in some 40 countries. The Norwegian state is majority owner. (dpa)