GMB Scotland has accused Labour of abandoning North Sea workers in a way comparable to the loss of more than 200,000 coal mining jobs in the 1980s.
The warning comes days after Exxon Mobil announced the closure of its Mossmorran plant, following the shutdown of the Grangemouth refinery earlier this year.
Louise Gilmour, GMB Scotland Secretary, said ministers were “sleepwalking” into another “industrial catastrophe”.
She told the Daily Record: “All the promises of new jobs being made to oil and gas workers today are the same promises made to miners 40 years ago.
“They meant nothing then and, without urgent action, will mean nothing now. A needless, industrial calamity is unfolding right now, today, while ministers talk about jobs tomorrow.
"The voice of energy workers must be heard and heeded instead of empty words and hollow promises.”
The union is urging Chancellor Rachel Reeves to reduce the windfall tax and approve the Rosebank field. Gilmour added: “The need to safeguard this crucial sector could not be more obvious or urgent.
“We will need oil and gas for years as we transition to renewables and we will need the skills and experience of oil and gas workers to make that transition happen.
“The need for an industrial strategy driven by ambition and investment that can build on those skills could not be more urgent.
“We must remember our industrial history or be condemned to repeat it.”
A DESNZ spokesperson said: “We have taken rapid steps to deliver the next generation of good jobs for North Sea workers in a fair and prosperous transition.”