Norway union warns of oil service strike, may hit output

(Adds comments from oil industry, Safe union)

OSLO, July 7 (Reuters) -

** Labour union Industri Energi on Thursday said a large number of workers at Norwegian oil service firms will go on strike later this year unless a wage deal is found in upcoming mediation

** Voluntary wage talks for 6,500 union members at around 60 companies broke down on Wednesday

** "A strike may hit output," Industri Energi union leader Leif Sande told Reuters. Still, a strike will most likely be months away

** Workers are not allowed to strike unless mediation by a state-appointed mediator has been attempted. Industri Energi did not specify how many of its members would initially go on strike, but said the numbers would be extensive

** A smaller trade union, Safe, struck a deal for its members late on Wednesday, but Industri Energi said it would demand larger wage increases than those obtained in the Safe deal

** Industri Energi also said it believed the deal signed by Safe and the Norwegian Oil and Gas Association (NOG (Taiwan OTC: 5279.TWO - news) ) was illegal, and added it would take the matter to Norway's Labour Court

** Industri Energi said mediation would only take place after the legal matter has been resolved, and a potential strike could consequently be months away

** The Safe labour union and NOG both defended the deal they signed on Wednesday

** "We've done nothing wrong, this is the way we've always negotiated," Safe leader Hilde-Marit Rysst told Reuters. "We would never have signed if we didn't believe we'd achieved a good deal."

** An NOG spokesman said the association had followed the law and a long-established practice, adding that it expected mediation would eventually take place some time after the summer holidays (Reporting by Stine Jacobsen, editing by Terje Solsvik)