A whistleblower claims an out-of-hours GP service covering 250,000 patients in parts of Somerset is using senior nurses when doctors cannot be recruited to work the shifts.
The firm, Harmoni, regularly employs advanced nurses to work eight-hour overnight shifts covering districts of up to 150 square miles, the whistleblower has told a national newspaper.
In times of extreme staffing shortages, there has been just one advanced nurse practitioner working overnight in North Somerset.
Harmoni also holds the contract to run the new NHS 111 helpline number in parts of Somerset and Wiltshire.
Bath & North East Somerset Clinical Commissioning Group has delayed implementing the service due to technical issues.
Harmoni handle calls to the 111 number in North Somerset and then pass the information to a company called BrisDoc, which makes the visit to the patient's home.
A new contract for providing out -of-hours GP services for Bristol, North Somerset and South Gloucestershire was awarded to a different service provider, BrisDoc, last month.