The GMB union said almost 3,000 ambulance workers in the Midlands will go on strike on December 21 and 28.
The action includes West Midlands Ambulance Service (WMAS), where paramedics, emergency care assistants and call handlers will walk out for 24 hours on both days.
It is likely to mean people who require 'non-emergency' assistance not being responded to. Unison and Unite members will be on strike in other parts of the country.
GMB says the Government's offer – an average of 4.75 per cent for NHS staff agreed by an independent review body – represented a huge real terms pay cut.
Conservative MP Marco Longhi said he was opposed to the strikes.
The Dudley North MP said: "While everybody wants to be paid more, and I am on record saying that front line staff do deserve it for the work they do, it has to be reasonable – that is why it’s an independent NHS body that decides and not politicians.
"So I disagree with union bosses’ stance. Using people’s ill health as a weapon to force government intervention is not right.
"NHS frontline staff command my respect and that of most people. The moment somebody dies or comes to harm through strike action there will be a steep decline in everybody’s goodwill towards them.
"I would urge staff to reconsider and not align themselves with union barons on six-figure salaries."
Stourbridge Conservative MP Suzanne Webb, said: "I admire and thank NHS staff for all they do. I know ambulance crews are at the sharp end this winter and they must cope with cost of living pressures like everyone.
"However, NHS staff will see their pay packets rise by at least £1,400 this year. Those on the lowest salaries are receiving up to 9.3 per cent extra. This is the best the Government can do.
"The Health Secretary was very clear when he said that any further one per cent rise in pay for all staff on 'agenda for change' contracts would cost an extra £700 million.
"The country simply cannot afford these sums."
Rachel Harrison, GMB national secretary, said the decision to walk out showed just how "desperate" workers had become.
"This is as much about unsafe staffing levels and patient safety as it is about pay," she said. "A third of GMB ambulance workers think delays they’ve been involved with have led to the death of a patient.
"Something has to change or the service as we know it will collapse.
"GMB calls on the Government to avoid a winter of NHS strikes by negotiating a pay award that these workers deserve."