Doctors are being offered thousands of pounds in bonuses to reduce the number of patients being referred to hospital, an investigation has found.
GPs are being paid up to £11,000 to stay within targets for outpatient referrals and follow-ups, doctor's magazine Pulse reported.
This can include cancer referrals and emergency admissions.
Critics have called the scheme "highly unethical" and "very concerning".
It goes against the General Medical Council's guidance that doctor's must not accept any "inducement, gift or hospitality".
The 'bonus' is also at odds with the recently announced NHS cancer strategy - which promised an 80% increase in tests for cancers.
The UK has the worst survival rates for cancer in Western Europe, which is largely down to late diagnosis.
The Pulse magazine found nine Clinical Commissioning Groups (CCGs) - a group of GPs who work together to shape local health services in England - were being offered incentives to cut referrals.
NHS North-East Lincolnshire CCG - which is offering £6,000 to GPs to reduce outpatient referrals to the same level as the 25% of practices who have the lowest referral rates - including two-week urgent cancer referrals
NHS Birmingham South Central CCG - which is offering £11,000 to cut new outpatient attendances, follow-ups, A& E attendances and emergency admissions by 1%
NHS Lambeth CCG - which is offering payments for GPs moving towards the average 2014/15 referral rate per 1,000 patients
Another six CCGs in London also offer incentives for GP practices to cut referrals, Pulse reported.
The investigation comes as the NHS tries to save £22 billion by 2020.
Dr Maureen Baker, chair of the Royal College of GPs, called the 'bonus' scheme a "preposterous idea".
She added: "It is deeply insulting and demeaning, as well as being highly unethical, to suggest that offering GPs money will change the way in which we care for our patients.
"Most worryingly, it undermines the doctor-patient relationship and the trust that underpins it."