Patients could be put at risk by new centres that step in after a GP has referred a patient to a specialist, a leading doctor says.
Referral management centres, which are already operating in parts of England, allow nondoctors or clinicians who have not seen a patient to decide if a referral to consultant care is valid.
BMA Welsh council chair Tony Calland said the practice is "totally unacceptable" and wants to stop the centres being introduced in Wales. He has written to Welsh health and social services minister Brian Gibbons.
He said: "We are concerned that the concept might be introduced across Wales with little evidence to show such systems are more effective than GPs acting in their traditional role of gatekeeper to secondary care."
NHS managers say the system speeds up the referral process and improves outcomes for patients.