Norway oil and gas workers threaten strike, but would not initially hit output

OSLO, June 3 (Reuters) - Some 573 members of Norway's Industri Energi oil and gas union plan to go on strike from June 12 onwards if state-brokered mediation with employers fail, but output would initially remain unaffected by a conflict, the trade union said on Friday.

The union members plan to strike at nine offshore installations, including the Njord A, Valhall and several Oseberg platforms, the union said in a statement. (Reporting by Nerijus Adomaitis and Nora Buli, editing by Terje Solsvik)