Around 450 staff from the Yorkshire Ambulance Service are on strike today.
The 24-hour strike by Unite Union members, started at 6am this morning.
David Whiting, Chief Executive, of the Yorkshire Ambulance Service NHS Trust, said contingency plans were in place, and that every effort would be made to reach patients as quickly as possible.
He added: “We recognise the legal right for those of our staff who are members of the union to participate in industrial action, but our focus is to balance that right with the need to first safeguard patient care and safety.
“However, I do not believe that industrial action in this form is in the best interests of patients, and it is deeply concerning for a trade union representing ambulance service workers to strike without making any concessions to patient safety.
“Throughout the 24-hour period of the strike, and the continuous overtime ban that Unite the Union commenced on 26 March 2013, our focus will be on taking steps to maintain operational cover to sustain effective and safe services.”
He urged members of the public to use the 999 service wisely during the strike, for patients with serious and life-threatening conditions only. He said people should only call 999 for an ambulance in an emergency when it is obvious that someone has a life-threatening or serious illness or injury.
Anyone requiring advice or treatment for a non-emergency situation or minor ailment should consider options such as self-care, a visit to a local pharmacist, GP surgery or walk-in centre.
The organisation receives an average of 2,050 emergency and urgent calls per day and employs over 4,300 staff.