(Adds quotes, detail)
OSLO, Oct 3 (Reuters) - Workers at three onshore plantsserving Norway's oil and gas industry will strike from Oct. 7unless they get a new wage deal, the SAFE labour union said onMonday, potentially threatening Britain's natural gas supplies.
Some 338 workers at Statoil's Melkoeya LNG plant,Shell's Nyhamna natural gas processing plant andExxonMobil's Slagen refinery terminal would go on strikeif talks on a new pay deal break down, the union said.
The Melkoeya plant turns gas from the Arctic Snoehvit fieldinto liquefied natural gas (LNG) which is shipped worldwide,while Nyhamna supplies about 20 percent of Britain's natural gasdemand from the giant Ormen Lange field offshore Norway.
"The onshore facilities would shut down, and would stopreceiving both oil and gas," union official Roy Aleksandersentold Reuters.
Shell and Statoil both said they were studying the impact ofa strike.
"We're awaiting the outcome of the mediation and areconsidering internally what the consequences of a potentialstrike could be," a Shell spokeswoman said.
"We are working to assess which consequences thispotentially could have for us," said a Statoil spokeswoman whodeclined to comment further.
ExxonMobil was not immediately available for comment.
The negotiations will take place on Oct. 6. (Reporting by Stine Jacobsen, writing by Terje Solsvik, editingby Nerijus Adomaitis and Jane Merriman)
