West Midlands Health workers are set to hold a fresh round of strikes on May 2 in the long running dispute over pay.
Unite the Union said its members at the South Central, South East Coast and West Midlands Ambulance Trusts along with workers at Christies NHS Foundation Trust, Christies Pathology Partnership, East Lancashire Hospitals NHS Trust, and Sandwell and West Birmingham NHS Trust will all take part in industrial action on May 2.
The announcement comes after some patients across England waited more than two days for an ambulance to arrive, according to data collected by Labour from Freedom of Information requests.
Unite members will vote on whether to accept or reject the Government's pay offer aimed at resolving the dispute on April 28.
Unite says many members remain unhappy with the deal and therefore are preparing for another round of industrial action.
General secretary Sharon Graham said: "Unite has been upfront and honest that it did not believe that the pay offer was good enough for NHS workers.
"A lump sum payment and yet another real-terms pay cut doesn't meet the challenges faced by NHS workers.
"Where our members have indicated that they want to swiftly return to the picket line, Unite is ensuring they are able to do so."