Creeping rationing of NHS care in England is making patients suffer unnecessarily, doctors are warning.
People needing knee and hip replacements are having to wait longer in pain for operations, the British Medical Association says.
And relatively minor treatments - such as varicose vein removal - are being scrapped altogether, medics at the BMA's annual GP conference will say.
Ministers say front-line services should not be affected by budget cuts.
But GPs believe the problems are being caused by the drive to make savings.
The NHS has been told to make up to £20bn of savings by 2015.
GPs 'increasingly worried'
A series of motions has been put forward at the conference, which starts in Liverpool on Tuesday, warning about the impact of cuts.
One motion says the principle that the NHS is "free at the point of access" is now misleading.
It has already been well-documented that procedures such as varicose vein removal and fertility treatment are being rationed.
But GPs will say it has gone much further than that recently.
Speaking ahead of the two-day conference, Dr Richard Vautrey, deputy chairman of the BMA's GPs committee, said: "Most people understand the NHS is not a bottomless pit and there are limitations to what can be done.
"But GPs are increasingly getting worried about rationing. There are huge variations in what can and can't be provided from place to place.
"We are also seeing more restrictions on when we can refer patients. It means people needing things such as hip and knee replacements wait longer and suffer unnecessarily."
The issue of charging patients for treatments not available on the NHS is also likely to be discussed.
Restrictions mean treatments for problems such as minor skin surgery are not always available.
Some GPs are trained to provide these and could do so privately but are prevented from doing so by current NHS rules.
Some doctors are lobbying for this restriction to be lifted, although there are concerns it could compromise the doctor-patient relationship.
Health Minister Lord Howe said: "Last year made we made it clear that it is unacceptable for the NHS to impose blanket bans for treatment on the basis of costs.
"That is why we banned Primary Care Trusts from putting caps on the number of people who could have certain operations and from imposing minimum waiting times."