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OSLO, June 30 (Reuters) - A Norwegian appeals court ruled in favour of the government in a lawsuit brought by investors who argued Norway's cut in gas pipeline tariffs was unlawful and would cost them 15 billion Norwegian crowns ($1.79 billion) in lost earnings through 2028, one of the plaintiffs said on Friday.
The decision upheld the 2015 verdict of a lower court, which said the government acted within its rights when it lowered tariffs for transporting gas through offshore pipelines, Njord Gas Infrastructure said in a statement.
"The Court has decided in favor of the Norwegian State," it added.
The lawsuit was brought by Solveig Gas, Silex Gas, Njord Gas Infrastructure and Infragas, which hold a combined 44 percent stake in pipeline joint-venture Gassled.
The firms are owned by Allianz ALVG.DE , UBS UBSG.VX , the Abu Dhabi Investment Authority and the Canada Pension Plan Investment Board, among other investors.
At least one of the partners, Silex Gas, told Reuters ahead of the verdict it would consider an appeal to the Supreme Court if it lost this round, but would also be open for discussion for a settlement option with the state.
If it does appeal to the Supreme Court, the company and the rest of the plaintiffs must do so by a September 16 deadline.
The Norwegian government owns 45.8 percent of Gassled via state-owned Petoro, while majority state-owned Statoil STL.OL has 5 percent.
Some of the companies involved have said the unexpected decision to change the gas transportation costs had hurt the image of Norway as predictable country to invest in.
The government cut tariffs shortly after the four firms bought their stakes in Gassled in 2011 and 2012 from ExxonMobil XOM.N , Total TOTF.PA , Statoil STL.OL and Royal Dutch Shell RDSa.L for a total of 32 billion Norwegian crowns.
The new, lower tariffs apply for gas transport agreements signed from Oct. 1, 2016 onwards.
The oil and energy ministry said last September the cut was aimed to help petroleum companies develop more gas resources, and was in line with its long-standing policy to keep a real pre-tax return on total capital investments in transportation infrastructure at around 7 percent.
"The new tariffs will continue to generate a reasonable profit in Gassled," the ministry said back then.
($1 = 8.3742 Norwegian crowns)