Around 150 contractors at energy plants at St Fergus and Mossmoran have begun week-long strikes in a dispute over pay.
Members of Unite the Union walked out on Monday after three-quarters of workers backed strike action.
The union said that strike action by members, who are largely maintenance and repair contractors, will have a “severe impact”.
An overtime ban has also been put in place for 12 weeks.
However operators do not anticipate there to be any impact on production at the sites.
The dispute involves contractors from the firm Kaefer, however Unite the Union have blamed Shell, saying they would have to fund any deal.
The union says that pay is linked to a national agreement but that workers at the two Scottish plants didn’t get the supplementary cost of living payment.
Vic Fraser from Unite the Union said members did not want to go on strike and just wanted support amid soaring bills.
He told STV News: “Like everybody else in this country, the cost of living crisis has impacted everybody’s wage.
“There was no cost of living payment made by Shell or Kaefer last year, and again this year there has been no cost of living payment.
“We don’t want to stalemate. Our members don’t want to be on strike.They just want some support with the cost of living crisis that everybody has faced over the last two years.”
Kaefer have said that they are satisfied that their current pay is above industry average.
They added there is no option for further pay but that the firm remains open to discussions.
Shell, who operate the sites, say they are encouraging discussions between the two sides to take place.
However, Unison accused Shell of being a major stumbling block in these talks.
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