Ambulance workers in the Unison union are to stage two more strikes in the dispute over pay and staffing.
Members of the union at five ambulance services in England have announced walkouts on Jan 11 and 23.
The strikes will affect London, Yorkshire, the North West, the North East and the South West, and follow action by members of the Unison, Unite and GMB unions on Wednesday.
GMB members at ambulance trusts are already due to take part in a further wave of strikes on Dec 28.
Unison said the announcement of new strikes was a direct result of the Government’s “repeated refusal” to negotiate improvements to NHS pay this year.
The January strikes will each be for 24 hours, from midnight to midnight, and involve all ambulance employees – not just the 999 response crews, as was the case on Wednesday.
Steve Barclay, the Health Secretary, infuriated union leaders on the eve of Wednesday’s action by claiming they had made a “conscious choice” to harm people.
Christina McAnea, the Unison general secretary, said: “It’s only through talks that this dispute will end. No health workers want to go out on strike again in the New Year.”
Ministers are understood to be keen to see next year’s pay award delivered more quickly in the hope that could break the deadlock with health unions.
But Ms McAnea said: “Speeding up next year’s pay review body process won’t solve the current dispute, which is about the pitiful amount the Government gave health workers this year.