Their union has formally rejected the action by Aberdeen-based Wood Group, calling it "outrageous".

Sandy Bremner reports on the action threat

The dispute involves 118 employees working on platforms in Shell's Brent oilfield.

Management have asked the workers to vote on wage cuts of between �3,500 and �6,000 as the company tries to reduce costs.

The union has rejected the ballot

General Secretary of the OILC, Jake Molloy, told BBC Scotland that the ballot was similar to asking turkeys to vote for Christmas.

"It's outrageous, it's never been heard of," he said.

Mr Molloy strongly criticised the way he said the Wood Group planned to organise the vote.

"Each ballot will have a number on it which corresponds to an employee.

"If there's anything untoward on the ballot sheets, if it's spoiled, if it's rejected in any way by individuals, then they will have their rates cut automatically by �6,000," he alleged.

The cuts are part of an efficiency drive

Mr Molloy said the union planned to apply a range of sanctions short of a strike. If the company refuses to "back down" the OILC would support all 118 workers at industrial tribunals.

"It's clear they have taken enough," he continued. "They are not prepared to accept any more intimidation.

"They are going to challenge it in any way they can and most likely that will come through legal action as opposed to industrial action."

The company said the ballot was part of an internal consultation process. Management is expected to respond in more detail later to the union's reaction.