Dansk Olie and Naturgas, Denmark's state controlled oil and gas group, has agreed to buy Statoil's assets in the Danish part of the North Sea for 1 billion Danish kroner ($123 million) to counter the threats of an increasing competition. DONG is buying forty percent of the Siri and Stine fields and 18.8 percent of the Lulita field, Norway's biggest oil company said in an e-mailed statement. Statoil will book a net gain of 700 million Norwegian kroner ($84 million) in the third quarter. The Danish company plans to spend at least ten billion Danish kroner to expand as competition intensifies and the Liberal Conservative government plans a DONG stake sale in the years ahead. The Danish company has just a sixth of the sales of rivals such as Ruhrgas, the biggest German natural gas company. Set up three decades ago to safeguard Danish energy supply, DONG started oil exploration in the 1980s and has a stake in all Danish licenses passed out since 1984, typically of twenty percent.