The Norwegian Petroleum Directorate said its latest estimate was around 480 billion cubic feet of oil equivalents, an increase of 1.5 billion compared to last year's estimate. The government said that, under current market conditions, the increase equates to $268 billion.
Norwegian Energy Minister Ola Borten Moe said the new estimates indicate there's plenty of reserves on the country's continental shelf.
"Our coordinated focus on increased production, the development of discoveries, exploration in mature and immature areas, and the opening up of new areas is supporting both the short-term and long-term aspects of the petroleum industry," he said in a statement.
Norway is the largest oil producer in Europe and the second-largest exporter of natural gas after Russia. Production is expected to decline this year but rebound by 2014.