Patients' lives could be put at risk by deploying specialist NHS paramedics who normally deal with the most serious emergencies to non-urgent call outs, it has been claimed.
South East Coast Ambulance Service's (Secamb) critical care paramedics (CCPs) are being brought into the overall cover plan system to make them available to respond to all types of call.
The change, revealed in a memo leaked to the Guardian, has provoked criticism among CCPs who fear lives could be endangered by them being tied up with non-urgent calls instead of dealing with life-threatening emergencies.
The Trust has defended the move, saying that with high demand and a poor response time performance it could not continue the current model of not sending CCPs to some categories of patient.
The change will run until the end of March 2017 when it will be reviewed. One CCP, who declined to be named, told the newspaper: "People will suffer because of it.
"The risk is of death among patients who could have been saved, maybe because we were tied up dealing with a minor ailment such as a cold, toothache, period pain or any of the other rubbish that people dial 999 with.
"It could be that we're with Mrs Jones who, after having back pain for four years, suddenly decides to call an ambulance about it.
"Secamb have kept us away from stuff like that for years. That system has worked. We have saved a lot of people as a result of that, including resuscitating people who were in effect dead, and now this."
Secamb, which covers Kent, Surrey, Sussex and north east Hampshire, was put into special measures in September after the Care Quality Commission (CQC) ranked it inadequate. The change is part of its recovery plan.
The Trust repeatedly came under fire earlier this year over a high-risk scheme - which has now been abandoned - to delay ambulances to patients.
Under the controversial plan, the Trust gave itself up to 10 extra minutes to reassess what type of advice or treatment some patients needed, and whether an ambulance was really necessary.
On Boxing Day, the Trust's on call strategic incident commander Richard Webber said it was facing "significant demand", with a 10% increase compared to last year.
The high volume of emergency 999 calls meant some patients were being expected to wait longer for an ambulance while the Trust focuses on life-threatening calls, he said.
A Secamb spokesman said: "As part of our recovery plan, and in order to maximise the clinical care we are able to provide to all of our patients, the Trust has been reviewing how to best utilise operational and clinical staff.
"This review will see critical care paramedics brought into the Trust's overall system status cover plan, meaning they will be available to respond to all types of call. The change will be reviewed at the end of March 2017.
"This decision has been taken following careful consideration by the Trust's exec, including the three clinical directors and taking in the findings of a recent Quality Impact Assessment.
"The Trust Executive recognises the valuable clinical contribution that CCPs make to our most seriously ill and injured patients as highlighted in the assessment.
"However, it also felt that while demand remains high and our response time performance for all calls poor, the current model of not sending CCPs to some categories of patient, could not continue."
The Trust said a decision had also been taken not to recruit to the paramedic practitioner course due to start in March and the CCP course due to start in September. Those currently on courses will not be affected.
"The Trust believes these decisions will allow a broader review to take place as to how it deploys and utilises its specialist paramedics in the future," the Trust spokesman said.
"We appreciate that these changes will cause anxiety and uncertainty for staff but it is essential that we utilise all our resources to the maximum benefit of all our patients."