More strike dates have been announced by members of the Welsh Ambulance Service.
Unite has said two 24-hour strikes will take place on the 19th and 23rd January.
Members of the union voted by a margin of 88% for industrial action over a pay dispute. It comes after ambulance staff and members of the GMB Union walked out in December last year.
During that strike, some of those on the picket line had to leave to deal with the huge number of emergency calls coming through to the service.
People across Wales were also urged to only call an ambulance in life-threatening and serious emergencies with many 999 calls missed.
Unite has said it will agree to emergency ‘life and limb’ cover provisions during its walkout later this month.
The union's general secretary, Sharon Graham has said: “Unite will stand 100 percent behind our Welsh Ambulance members who are striking to save our NHS.
"They see first-hand every day how the NHS is collapsing. A decent pay increases is the only way to improve NHS recruitment and relieve the crippling pressure on ambulance services.
“The roots of this dispute may be in Westminster, but the Welsh Government needs to move to improve its pay offer if we are to avoid a prolonged dispute.
“This union stands ready for serious negotiations with governments in all nations, Wales included. We now urgently need action to address the NHS pay and staffing crisis.”
Meanwhile the regional officer for Wales, Richard Munn, has said that the strike is more than just about pay.
"Staff are exhausted and stressed and the meagre pay increase was the final straw for most.
“We know that the Welsh Government has limited finances but Unite is imploring them to come to the table with an increased offer, as was the case in Scotland.
“Unite recognises that the crisis has arisen because of the Westminster government’s deliberate failure to fund a decent NHS pay rise across the UK.
"While the UK government seems oblivious to the anger and frustration of NHS workers, the Welsh Government has shown that it does understand the issues. But now it needs to act.”
The Welsh Conservatives blamed "25 years of crippling NHS mismanagement" in Wales by the Labour-run Welsh Government for the strikes.
The party's shadow health minister, Russell George, said: "Only last month, Wales saw the slowest ambulance response times on record.
"Let me be clear, this is not the fault of our hard-working Welsh ambulance members - the blame lands firmly at the door of Labour ministers.
"This cost-of-pain crisis is a living nightmare for those left wondering if a life-saving ambulance will arrive or not, or whether they will be seen in A&E in a reasonable time.
"Labour need to get an urgent grip on the NHS and stop breaking all the wrong records."
The Welsh Government, which decides how much Welsh Ambulance Service employees are paid, has said it cannot offer a better offer without more funding.
A spokesperson said: “We understand and respect the strength of feeling among Unite members at the Wales Ambulance Service which have led to this strike action.
“Following the ballot result, we will work with the ambulance service and health boards on their contingency plans. The public should be assured that arrangements will be made with unions to ensure there will always be a safe level of staffing, with life-saving and life-maintaining care being provided during any industrial action.”
The announcement of fresh strikes come as the Director of the Welsh NHS Confederation has described the service as being “on a knife edge” in terms of its ability to cope with sustained levels of pressure.
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