Hospitals in the South East are being told to delay routine patient appointments for eight weeks, otherwise they will not be paid for them.
Consultants are told to work to a minimum eight-week waiting time
The minimum period is being enforced by primary care trusts because a drive to meet government waiting time targets was costing too much money.
Hospital consultants and GPs in Kent and West Sussex said being told not to see patients was "unethical".
NHS South East Coast said it had to "live within its means".
The strategic health authority (SHA) - which covers all hospital and primary care trusts in Kent, Surrey and Sussex - said its forecast deficit for the current financial year was £104m.
A letter sent to all the trust chief executives said routine patients should not be seen "too promptly".
It concluded that if hospitals failed to reduce the level of routine referrals under eight weeks, the SHA would "support non-payment [by the relevant PCT]".
Dr Gordon Caldwell, a consultant physician at Worthing Hospital in West Sussex, raised the issue recently with his local MPs.
Dr Caldwell told the BBC News website: "I've become convinced the NHS is being managed so badly that the electorate needs to know.
"It's not just irritating now, it's dangerous.
"There's a split among the consultants - are we obedient little workers, or do we do what's ethical and right for the patient?"
Staff and consultants at Worthing Hospital have criticised the ruling
Dr Caldwell said the Worthing and Southlands Hospitals NHS Trust would lose £215 for each routine referral accepted within eight weeks.
Tim Loughton, the Conservative MP for East Worthing and Shoreham, asked a Commons question about the policy on Wednesday.
He said: "These consultants believe it's unethical for them not to continue to see their patients, and they don't want to spend their time sitting around twiddling their stethoscopes even if it means the hospital doesn't get paid."
Dr Gary Calver, a GP in Folkestone, Kent, saw the SHA letter at a British Medical Association meeting.
"It clearly means there is financial pressure to make sure patients aren't seen as quickly as they could be, even though doctors and nurses are able to see them," Dr Calver said.
NHS South East Coast said in a statement: "The local NHS is required to ensure that all patients are seen within the target times and, at the same time, to ensure it lives within its means."