Dozens of Petrofac employees on BP platforms in the North Sea have voted to go on strike.

Members of the Unite union voted to down tools amid a dispute around three-week offshore working patterns.

100% of members who voted decided to take industrial action, of a 75% turnout.

It is understood 43 workers will take part and dates will be announced in “due course”.

The dispute is separate from on-going strike action taking place with Petrofac and Aker Solutions workers on Total’s Alwyn, Elgin and Dunbar platforms and the Shetland gas plant.

Unite said members are working three weeks on, three weeks off (3:3) rotas with no holiday entitlement and are seeking a change to either a 3:4 or extra holidays.

Regional officer John Boland said: “Unite’s Petrofac members working on all BP platforms have voted emphatically for industrial action.

“By 100%, the workforce are rightly demanding that their rotas be changed from the hated 3:3, and to have more time off with their families.

“So, we call on BP and Petrofac to listen to our members’ reasonable request, and to put the welfare of their workforce first.”

Petrofac and BP have been approached for comment.

Separately to Petrofac, BP staff work a 3:4, 3:5 rotation.

Three-week rotas have been the focal point of the separate strike action on Total platforms by Petrofac and Aker Solutions staff.

Last year operators including Shell and Apache opted to change their 3:3 rotations amid claims it could have a detrimental impact on workers’ families and their mental health.