Members of the GMB union have voted for strike action on Equinor’s Mariner platform.
The strike is over a dispute on a pay, terms and conditions offer made by Aker Solutions management.
Nearly 80% of those balloted voted for the strike, which is likely to take place in the autumn.
GMB follows the Unite union which has also voted to strike on Mariner.
GMB national officer Ross Murdoch said: “GMB members have now let their feelings be known to Aker Solutions.
“They are prepared to take industrial action to vent their frustration over the way they feel their employer is treating them on this very lucrative contract.
“It is now incumbent on Aker to engage with GMB Union and find a resolution that avoids potentially costly operational disruption and reputational damage on this contract.”
A spokesman for Aker Solutions said: “Aker Solutions was today notified by trade unions Unite and GMB that, following a recent ballot, their members employed by Aker Solutions on the Mariner project have voted to initiate strike action.
“This is a disappointing development following the presentation of an enhancement to terms and conditions worth up to £8,000 per employee. Aker Solutions will now seek further discussions with the unions regarding their proposed steps to resolution.”
It follows an unofficial action on Mariner in April when workers downed tools for eight hours.
Meanwhile, strike action has officially begun today, halting production on Total’s Alwyn, Dunbar and Elgin platforms.