The Department for Transport says its "disappointed" that 4,000 members of staff have decided to strike today.
The PCS union says members will hold 15 minute demonstrations across Wales.
We are disappointed that the PCS union have decided to take industrial action while we are still engaged in consultation with them about their concerns over changes within the department.
Contingency plans are in place to ensure delivery of essential services to the public continues throughout the planned strike action.
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There will be some patchy rain but many areas will be dry for much of the time.