Union members working on the new gas plant project at Sullom Voe have voted overwhelmingly in favour of industrial action.
Ninety-four per cent of workers affiliated to the Unite union who took part in a ballot have backed calls to down tools following accommodation concerns and transport arrangements.
A similar percentage of GMB members who voted are also believed to be in favour of stoppage.
The workers are all involved in the construction of the £800 million development being built by Petrofac for French oil giant Total.
It is not known at this stage exactly what form the industrial action will take.
Union leaders are due to hold discussions with stewards to plan for action, possibly in the next couple of weeks.
Talks between unions and management are expected to take place before the walk-out in the hope of finding a resolution to the dispute.
The ballot was held last month amid a row about shared accommodation on barges and in an accommodation block.
John Taylor of the Unite union told The Shetland Times:
“We’ll look at dates for industrial action but we also expect the employer to contact us to continue discussions.”
Members believe they should be entitled to an allowance which, they say, was given to managers when they stayed in shared accommodation.
The dispute also focuses on calls for travel allowances to be paid, after workers’ concerns about bus journeys taking up to one hour each way to and from work.
More to follow.