A family doctor in Dacorum has warned an NHS shake-up will 'destroy general practice as we know it'.
Dr Tony Hall-Jones claims a 'polyclinic' employing scores of GPs is planned for the site of Hemel Hempstead Hospital which will effectively put other practices out of business.
The Tring doctor says while the privately-run polyclinic will provide 'supermarket-style opening times', it will also result in 'sausage-machine healthcare'.
"It will change forever the way in which GPs and their patients interact," he said.
"Patients need to know the risks that are being taken in their name."
However, the issue appears to have split opinion among local doctors with some saying a polyclinic could be a good thing.
In October full A&E services will close in Hemel Hempstead to be replaced with a GP-led urgent care centre. Meanwhile planned surgery has been shifted to St Albans.
Dr Hall-Jones says alongside the urgent care centre there will be a polyclinic offering GP services to the entire borough.
Family doctors in the area will be faced with the choice of joining the clinic or going it alone, he claims, but will have little chance of competing with a private company.
"The nature of GP practices in west Herts is one of the best in the country. Patients will lose choice and the GP they have known for years and in it's place will come sausage-machine healthcare," he added.
But Dr Gerard Bulger from Bovingdon said a polyclinic could work in partnership with GP surgeries to provide a better service.
A private company could provide accommodation and peripheral services while GPs would manage the clinic.
Herts Primary Care Trust said the new health centre would be open from 8am to 8pm, seven days a week, with both bookable and walk-in appointments.
"Any new health centre is not designed to replace any existing services," a spokesman said. "It will increase access for people to see a doctor or nurse in the evenings or at weekends."