Some 10,000 members of the GMB, Unite and Prospect trade unions at the Sellafield and Capenhurst nuclear power plants were to start balloting this week after pay talks broke down.
But Prospect has called off its ballot in response to a new offer, while the GMB and Unite have postponed their votes.
The improved offer to Prospect members is a 2.5 percent basic rise, which is still well below inflation.
The GMB, meanwhile, has suspended its ballot for seven days in the face of threatened legal action. And Unite has delayed balloting until Friday of this week.
Peter Kane, GMB’s Sellafield convenor, said, “The company threatened us with a legal challenge if we balloted today.
“We spoke to our legal advisors over the weekend and decided it would be prudent to delay for seven days.”
The improved offer to Prospect came despite talks with all three unions in Penrith last Wednesday ending without agreement.
Kane said, “All the unions said we were a million miles apart.
“The company has made no contact with us since then.”
Workers rejected the original 2 percent pay offer by almost a six to one margin.