Around 11% of the 7,500 offshore oil and gas workers in Norway are threatening strikes if mediation talks fail this week.
Statements from the Industri Energi, Lederne and Safe unions have been issued threatening action after negotiations broke down last month.
Mediation is due to take place this Friday and Saturday in Oslo, with a strike to follow on June 12 if no deal is reached, Safe said.
The Safe union added that strikes “will not affect Norway’s gas exports in view of the situation in Europe in the first instance”, backed up by IE which said its members would not initially impact production in Norway.
Workers are seeking a pay rise above inflation and other changes to their contracts which have not been disclosed.
Lederne attorney Thomas Ostermann said: “As of right now we cannot speak more sincerely about the likeliness of a strike actually being put into effect, pending the outcome of the mediation process.”
In a statement to EV, he added: “Unless the mediation process breaks down, and based on the information available to us to this day, operations will run on Sunday.”
A strike would impact 10 installations in Norway including Oseberg East, Oseberg South, Njord A, Valhall, and Gudrun.
Equinor, the largest producer in Norway, said it is too early to comment on the impact to oil and gas production from the proposed strikes.
Safe said nearly 200 of its members would strike on June 12 if mediation fails.
IE has previously said that 573 members would strike, along with 74 from Lederne.