In a joint venture with state-owned Qatar Petroleum (QP), Norsk Hydro Chief Executive Eivind Reiten said on Sunday the plant would produce 570,000 tonnes a year.
If all goes to plan, the plant will be among the world's six biggest aluminium smelters with tentative plans to double capacity within a year.
Reiten said QP would own 51% and Norsk Hydro 49% of the primary aluminium plant and a dedicated gas-fired power plant.
Production is expected to start in 2008, and the plant south of the capital Doha would reach full capacity in 2009.
Norsk Hydro now sells about 3.3 million tonnes of aluminium annually, including 1.5 million tonnes of its own primary production and another 1.8 million from remelted scrap and ingots and metal products supplied by strategic partners.
Norsk Hydro shares closed at 475.50 Norwegian crowns ($77.69) on Friday.