Norway's state oil firm Statoil said on Friday that a strike by private sector workers would probably start cutting its oil and gas output towards the end of next week.
According to company officials, production is going on as usual as the strike by 85,000 private sector workers, including about 1,000 in the oil sector, gripped Norway for a third day.
Officials added that crude exports were still blocked at Statoil's 600,000 barrels per day (bpd) Mongstad terminal. The strikes have also prevented loadings from Norsk Hydro
's 430,000 bpd Sture terminal and from its gas facility at Kaarstoe.
Oil normally exported is going into storage tanks because tugboat operators are on strike, preventing tankers from docking to load as normal. Hydro says Sture's tanks will be full on May 12, and will then force field shutdowns.
Norway's main unions started the strike on Wednesday after members rejected a 2000 pay deal. The union is not currently in talks with employers on resolving the dispute.