The trust between doctors and patients is under threat if the government introduces "unethical" performance-related pay, a union has warned.
The British Medical Association (BMA) said ministers have to reconsider proposals to pay GP consortia a bonus for managing their finances well.
It has published guidance – Ensuring Transparency and Probity – aimed at groups of GPs who have formed into consortia on how to ensure transparency, honesty and decency.
It outlines how GPs will be able to provide care and make decisions about where that care takes place.
The guidance says it is "absolutely vital that the public, patients, other doctors and health professionals have the utmost confidence and trust that the commissioning decisions of GP consortia will be solely in the interests of patients, and with no actual or perceived vested interests or motives".
The document says the trust patients place in GPs is the "cornerstone of general practice" and must be maintained.
"Where GPs are both providing care and deciding where that care takes place, how it is provided and who provides it, there is a real risk that a doctor's probity may come into question."