Ambulance workers are to stage fresh strikes in a long-running dispute over working conditions and safety issues.

Members of Unite at the Yorkshire Ambulance Service will walk out for six hours from 3pm on August 29 and for the same time on September 2.

The union accused the local NHS trust of refusing to hold talks at the conciliation service Acas to try to resolve the 20-month-old row, which centres on new shift patterns.

Unite said new working conditions were imposed on staff, giving more responsibility to emergency care assistants and changing meal breaks.

Almost 400 union members have held a series of strikes since April 2013.

Unite regional officer Terry Cunliffe said: “Our members firmly believe that the public deserve a first-class, fully resourced ambulance service and, as they have shown on a number of occasions since April 2013, they have been prepared to strike to strongly make that case.

“We have been buoyed up by the support we have received from Yorkshire people and we thank them for that. Unite’s door is open for talks under the auspices of Acas at any time.”

 Ian Brandwood, executive director of HR at the Yorkshire Ambulance Service Trust, said: “We remain disappointed that Unite has decided to continue with yet more strike action.

“Once again, the industrial action will take place without any concessions for the most seriously ill and injured patients and we remain concerned over this type of action.

“We would like to reassure members of the public that we have robust contingency plans in place. We continue to focus on safeguarding patient care and are committed to minimising the level of disruption to our services.

“Throughout the period of industrial action we will be taking steps to maintain operational cover to sustain effective and safe services for our patients who find themselves needing emergency medical assistance. We will continue to make every effort to get to patients as quickly as possible, whilst maintaining high standards of patient care.”