Driving examiners are to stage a 48-hour strike from December 4, the day a new driving test is launched, in a dispute over working conditions.
The Public and Commercial Service union (PCS) said up to 2,000 of its members will take part in the walkout, warning that thousands of driving tests will be affected.
An overtime ban and work to rule will also be held, from November 23, which the union said could lead to last minute cancellations of tests across England, Wales and Scotland.
The union said examiners were being told to work longer, harder and for no extra pay when the new tests are introduced.
Union members voted by 84% in favour of strikes on a 70% turnout.
PCS general secretary Mark Serwotka said: "The actions of the Department for Transport in trying to force detrimental changes on to our members has backfired.
"Our members whose jobs are about ensuring our roads are safe for drivers and pedestrians have voted overwhelmingly to demonstrate that these changes are unacceptable.
"Ministers can avoid this strike action by instructing their officials in the Driver and Vehicle Standards Agency to scrap the plans and re-enter serious negotiations with PCS.
"If this strike goes ahead the blame lies squarely with the Government."