Some people trying to book an appointment at Burton Latimer Medical Centre have been forced to call more than 200 times before getting through.
Last year the surgery was told it required improvement by CQC inspectors, with concerns over the difficulty of getting through to the practice one of the issues raised.
Many patients have taken to social media to vent their frustration, with one user saying he tried to call 247 times before getting through, only to be told there were no available appointments.
With a number of housing developments in the town on the horizon, concerns are growing about how the surgery will cope - but Di Pegg, head of primary care for NHS England in Northamptonshire, says steps are being taken to address this.
She said: “Ensuring patients have access to safe, quality GP services is a priority for NHS England.
“Telephone access was one of the points raised by the Care Quality Commission’s recent report on its inspection of Burton Latimer Medical Centre.
“The practice has taken a number of steps to address this, and is continuing to work with us and Nene Clinical Commissioning Group to take forward further improvements.
“The practice has advised us that it will shortly be opening a number of new consulting rooms with the explicit aim of creating additional capacity to meet the needs of the growing population.
“We would remind any patient who is unable to make their booked appointment to let the practice know as soon as possible, so that their slot can be offered to someone else.
“Patients are also encouraged to register with the practice’s online service so they can book appointments over the internet.”
MP for Kettering Philip Hollobone says he is ready to escalate matters if things do not improve.
He said: “I have been contacted by one resident who has had problems with the medical centre in Burton Latimer.
“I would encourage any resident who is having difficulties with access to their GP, whether in Burton Latimer or elsewhere, in the first place to make a written complaint to their practice.
“Should the response to that complaint be unsatisfactory I stand ready to help local residents escalate matters further on their behalf to NHS England, so that complaints can be fully and satisfactorily resolved.”