Norway's Lederne labour union said on Wednesday it would escalate the action from Oct. 4 after dozens of workers went on strike at the Johan Sverdrup oilfield, western Europe's largest.

NOG said the strike could force shutdown of the Equinor-operated Gudrun, Gina Krog, Kvitebjoern fields and the Neptune Energy-operated Gjoea field.

In addition, production would have to stop at the associated Equinor's Valemon and Wintershall DEA's Vega fields, it added.

"The risk therefore exists that about eight percent of total petroleum production from the Norwegian continental shelf could be lost through extending the strike," NOG said.

Lederne plans to take a total of 126 union members on strike, in addition to 43 who stopped working at Sverdrup on Monday after state mediated wage talks with NOG failed.

Equinor said it could still maintain production at the 470,000 boepd Sverdrup field despite the strike.

Two larger offshore worker unions, Industri Energi and Safe, have agreed to new wage deals and will not go on strike.

Lederne said it was seeking better financial terms for its members and wanted the offshore wage agreement to cover its members who work at a remote control room onshore.

Equinor and other oil companies have been looking into ways to remotely control production at offshore fields to reduce the costs.

NOG said Lederne's demand fell outside the scope of the offshore wage agreement.

(Reporting by Nerijus Adomaitis; Editing by Victoria Klesty)