Two of the three unions that negotiated with oil firms will seek approval from their members before they formally approve the deal, the lobby representing employers and one union leader told Reuters.

"Agreement. No strike. But Lederne and Safe (trade unions) send the results to a referendum (of) their members," a spokesman for the Norwegian oil and gas lobby told Reuters. "They will have to answer (by) June 30."

Some 845 workers out of roughly 7,500 employees on offshore platforms had planned strike action from June 12 if the annual pay negotiations with employers failed, trade unions Safe, Industri Energi and Lederne had said.

(Reporting by Nerijus Adomaitis, editing by Terje Solsvik and Catherine Evans)