Ambulance services are likely to be hit today as thousands of workers in England and Wales join nurses in striking over pay.
Rachel Harrison, GMB Union national secretary, said the government could solve the dispute at any time.
“We have tried everything to raise pay, the issue that is causing this dispute, but the government will not listen and will not talk,” she said in a statement on Wednesday.
The strike will increase the strain on NHS services with hospitals saying the action would put patients at risk.
The NHS Confederation, which represents national health service organisations, said the strike risked patient safety.
“We cannot guarantee patient safety, we cannot avoid risks in the context of this industrial action,” chief executive Matthew Taylor told BBC radio on Tuesday.
The government said the “deeply regrettable” strike would result in fewer ambulances on the road.
The latest strike action comes as emergency and urgent care services across the country have experienced the highest levels of demand and delays.
