Ambulance staff will walk out on strike today.
Members of the Unite union at the Yorkshire Ambulance Service will stage a strike from 3pm on Saturday until 7am on Sunday, May 18.
Unite, which represents 375 ambulance workers, was de-recognised a year ago by management for collective bargaining on behalf of its members after raising concerns that budget cuts could hit patient safety.
Ian Brandwood, executive director of human resources at the Trust, said: “We are very disappointed that Unite has decided to go ahead with strike action this weekend despite recent constructive talks with senior representatives at the union.
“The trust has taken all reasonable procedural steps to resolve the dispute and has fully cooperated with the course of action agreed with the Advisory, Conciliation and Arbitration Service (ACAS).
“Once again the industrial action will take place without any concessions for the most seriously ill and injured patients and we remain extremely concerned over this type of action.
Mr Brandwood added the trust will continue to safeguard patient care and urged people only to call 999 when someone has life-threatening or serious illness or injury.
He added: “ 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, contacting the NHS 111 urgent care service or their GP, visiting a walk-in centre or minor injuries unit.”