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.
More top news
Four Labour AMs expressed their support for the Health Secretary to replace Carwyn Jones as Welsh Labour leader.
A host of global stars including Craig David, Jess Glynne, George Ezra and Florence and the Machine will head to the city for the event.
Smoke-free areas are expected to be in place in hospital grounds, school grounds and playgrounds by summer 2019.