The talks between the Norwegian Shipowners' Association (NSA) and the Safe, Industri Energi and DSO unions will resume at a later date under the leadership of a state-appointed mediator, and could end in a strike if those negotiations fail.
Any industrial action would most likely have only a marginal impact on production of oil and gas in the short-term, but could have a greater impact in the medium- to long-term as expansion projects and the start-up of new fields would be delayed.
Companies affected by the talks include Transocean, Saipem, Odfjell Drilling, Maersk Drilling, Archer, Seadrill and others.
The unions represent workers on mobile offshore units as well as platform drilling on permanent installations.
Under Norway's tightly regulated collective bargaining system, workers are only eligible to go on strike if the mediation also fails.
(Reporting by Terje Solsvik, editing by Gwladys Fouche)