NHS Sheffield has said a number of medical procedures will no longer be routinely available to patients in the city.
GPs will have to make the a case on a patient's behalf for the procedures, which include hysterectomies and varicose veins surgery.
NHS Sheffield said stopping the treatments, which were previously routinely available, would save money.
The Patients Association said decisions about treatment should be made by GPs.
The procedures have also been deemed by NHS Sheffield as having "limited clinical value".
Other procedures on the list include lower back surgery, grommet insertions and acupuncture.
Dr Zac McMurray, a local GP and joint chair of NHS Sheffield's clinical executive, said: "This isn't a decision we're taking lightly.
"All we want to do is make sure all the alternatives have been tried first and we want a bit of evidence that clinicians have followed best practice before they make the decision to go to operation."
Patients currently on waiting lists for the affected treatments will continue to have them as recommended.
Dr McMurray added: "We've got around £20m to find this year that we don't have.
"We're forced into doing this because of the financial situation to make sure we use the resource we've got for the benefit of all our patients."
Katherine Murphy, chief executive of The Patients Association said: "We have had some evidence where what is classed as non-important surgery is being postponed or cancelled for individuals."
She added that decisions about whether a patient should have an operation or treatment should be made by their clinician or GP, and that this should not be influenced by having to save money.