South Western Ambulance Service has declared a critical incident due to extreme demand faced following the four-day Christmas break.
The trust says on Wednesday there were 482 patients waiting for ambulances across the South West, with 106 patients awaiting handover at hospitals.
SWASFT’s Deputy Director of Operations, Wayne Darch, says demand for services is affecting response times getting to patients.
He said: “Please help us to help the patients who need us most by only calling 999 if a patient has a life-threatening condition or illness.
"If the condition of a patient is not life-threatening we may direct them to an alternative service. So please help us by accessing the right service for the care you need.
“We are doing all we can to manage these winter pressures and we are sorry that we are unable to respond to some patients as quickly as we would like. We will get to you as soon as we can.
“Please do not call back simply to ask for an estimated time of arrival of an ambulance. We cannot provide one, and it blocks our lines for other callers."
South Western Ambulance Service provides emergency and urgent care across Cornwall & Isles of Scilly, Devon, Somerset, Dorset, Bristol, Wiltshire, and Gloucestershire.