Union leaders representing North Sea oil workers seeking an extra four weeks' paid holiday per year are meeting to decide their next move.
Five unions are complaining that 7,000 offshore workers are being denied leave to which they are entitled under the Working Time Directive (WTD).
Most work offshore for two weeks followed by a fortnight's compensatory rest. But for many the rest is unpaid.
An employment tribunal last month ruled that the WTD legislation covered offshore installations, a decision dubbed by union leaders a "wonderful victory".
But a number of oil and gas companies are to appeal, and the unions fear it could take years to resolve.
The chief executive of the Offshore Contractors' Association, Bill Murray, said: "We have had clear legal advice there are very good grounds on which to base an appeal."
The energy companys have said they are happy to engage in "constructive dialogue" with union leaders.