Graham Thomas, one of two GPs working at the Corwen surgery, said a £52,320 rural support payment to the practice had helped kept it viable for at least 15 years.
But Dr Thomas said it may be forced to return to Betsi Cadwaladr University Health Board control unless its steps back from withdrawing a £52,320 year rural support payment.
If that happens then patients will wait longer to get an appointment and have a worse service, Dr Thomas told the Daily Post.
"The practice is usually being managed because it is unable to provide sufficient GPs to see patients so the health board will try and provide locums and that can be a real challenge for the health board.
"There just aren't the number of locums that are required," he said.
"And unless they've got contracts with the health board then the health board just can't produce GPs out of nowhere especially in rural Wales.
The health board said it was working with the practice to agree ongoing funding support, in line with the Welsh Government's GP sustainability assessment framework.
This would help the practice continue to provide a service for residents in Corwen and the surrounding area, said a health board spokesman.
"We are also finalising payment for additional cardiology services provided by the practice.
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