Hospitals and health centres in Huddersfield are to be hit by strike action.
The Government is facing a fresh wave of strikes by health workers in the new year amid the bitter dispute over pay.
Unison announced that its NHS members in England will walk out for 12 hours from 9am on January 29, while ambulance workers in the GMB union in England and Northern Ireland will strike on January 29 and 30.
The dispute has been raging all year after the Government decided not to accept a recommended 1% pay rise for all NHS staff.
Unison said its members will stage a second strike, for 24 hours, on February 24.
See gallery below of striking NHS workers in October.
NHS staff will also launch a work to rule between January 30 and February 24, including refusing to do unpaid overtime and making sure they take their breaks.
Health workers from 12 unions, including nurses and midwives, took strike action in October and November - many for the first time in their lives.
Lesley Hill, director of Planning, Performance, Estates and Facilities at the Calderdale and Huddersfield NHS Foundation Trust, said: “As on the previous days of action the Trust will have a detailed and robust plan in place to ensure our patients receive their care and disruption is kept to a minimum.”