Thousands of workers at the DVLA and Transport Department will go on strike tomorrow in the latest phase of a long-running dispute over jobs, office closures, pay and privatisation.
Members of the Public and Commercial Services union (PCS) in Swansea and other parts of South Wales will walk out for three hours from 2pm.
The union has been holding a series of stoppages across the country in recent weeks in a bitter row over cuts.
The PCS said more than 1,200 jobs at the DVLA were threatened under plans to close offices and transfer work to the agency's headquarters in Swansea.
PCS industrial officer Mike Hallinan said: "The number of jobs that could transfer to Swansea is unconfirmed. Many of them may prove to be temporary and the ongoing cuts programme makes it highly unlikely that there will be any net increase in staffing in Swansea.
"Most importantly, of course, these would not be new jobs at all, but the transfer of work from hard-working public employees whose future is now in jeopardy.
"Our members will be taking action tomorrow in opposition to the Department's whole programme of cuts, closures and privatisation. We believe that the Government should not be making public sector workers bear the burden of an economic crisis they didn't create."