Doctors' leaders are warning the financial crisis gripping the NHS is threatening patient care.
One in four NHS trusts was in deficit last year
The British Medical Association has written to Health Secretary Patricia Hewitt for a meeting after a quarter of NHS trusts ran a deficit last year.
Dr Paul Miller, chairman of the BMA's consultants committee, said job losses and department closures could be on the cards.
But the government said other actions could be taken to balance the books.
Two NHS trusts - one in Portsmouth and one in south London - have already placed restrictions on the recruitment of nurses and administration staff.
And several accident and emergency departments have closed across the country as health bosses try to make savings.
Trusts have blamed new contracts for GPs and consultants and the cost of drugs for the financial problems.
Dr Miller said future cuts would "pose significant threat to patient care and innovation in the NHS".
"We are deeply concerned that managers running frightened for their jobs are making knee-jerk decisions about the reduction or closure of services in response to short-term funding problems."
The committee's deputy chairman Jonathan Fielden said extra funding given to the top reaches of the NHS in recent years had not filtered down to the frontline.
He added that some services were being reduced at trusts which were performing well, to bail out those that were not.
The BMA is planning to survey doctors to determine just how widespread the problems are.
But Dr Gill Morgan, chief executive of the NHS Confederation, which represents health service managers, said she was disappointed that the BMA had attacked health bosses.
"It is simply untrue to say that managers who are taking decisions about how to balance their budgets, while maintaining high quality clinical services, have no appreciation of the long-term consequences for patients services as the BMA alleges."
She said the NHS financial deficit represented just 0.2% of the overall budget.
And she added that doctors had a role to play in trying to make savings.
A Department of Health spokeswoman said: "Patient safety is top priority for the NHS and any actions that trusts take to manage to reduce the deficits should not lower the quality of care provided to patients.
"We have encouraged the NHS to use a range of strategies in order to reach financial balance without reducing spending on agency staff."