Norway's Det norske oljeselskap and Aker Exploration said on Tuesday they had agreed to merge to create the country's second-biggest oil firm with a combined value of around $694 million.

Shareholders of Det norske, the biggest of the merging companies by far, will get 82 percent of the combined firm but industrial group Aker will become the largest single shareholder, with a stake of around 30 percent.

Aker owns some 76 percent of Aker Exploration but bought an 18.2 percent stake in Det norske in May and has since set about engineering the tie-up.

The combined company will be able to grow more rapidly, both through organic growth and by adopting a forceful approach to continued restructuring in the industry, the companies said in a joint statement on Tuesday.

Shares in Det norske fell 1.9 percent at 0814 GMT, Aker Exploration was untraded and Aker ASA rose 1.1 percent after the news. DNO International, which owns over 23 percent of Det norske, fell 1.4 percent against a 0.4 percent drop on Oslo's index .OSEBX.

Det norske and Aker Exploration have a combined market capitalization of 4.17 billion Norwegian crowns ($694.2 million), with Det norske comprising 83 percent of the combined value of the listed shares at Monday's close.

The deal is almost set at yesterday's closing price, but it's tilted toward Aker Exploration and, in my view, it shouldn't be, Carl Christian Bachke, analyst at Fondsfinans, said.

Aker's tightening its grip on Det norske, but it remains to be seen if the shareholder meeting in October will approve it.

The biggest shareholders, Aker and DNO International , have endorsed the merger, but some license-related issues still need to be clarified and the deal must be approved by shareholders at a meeting in mid-October, the companies said.

If the merger goes through, the new firm would be the second-biggest on the Norwegian continental shelf in terms of licenses and operations after Norway's national oil company StatoilHydro. The combined firm would operate 32 licenses and have 70 licenses in its portfolio, the firms said.

Det norske Chief Executive Erik Haugan would become head of the merged company, which will use the name Det norske. Kjell Inge Roekke, chairman of the board at Aker Exploration, would be put forward as chairman of the new firm, the companies said.

The merged company would aim to produce around 15,000 barrels per day by 2014 and 50,000 barrels per day by 2020, the groups said in a statement. It would have P50 reserves -- a measure of potential reserves -- of 852 million barrels of oil equivalents.

The merged company will also have long-term contracts with two floating rigs.

(Editing by Lin Noueihed)