Three-quarters of NHS bosses say patient care will suffer because of the current cash crisis, a survey suggests.
A quarter of trusts said they had made recruitment freezes
Two-thirds of acute trusts had had to close wards, the survey of 117 acute, primary care and mental health trusts in the Health Service Journal said.
The government predicts a £620m deficit in the NHS for the 2005-6 financial year, and the Royal College of Nursing says 400 nursing posts could be lost.
The Department of Health says there is more money in the NHS than ever before.
The Royal College of Nursing (RCN) says the NHS financial deficit could go as high as £1 billion.
Earlier this week Treasury officials warned the Health Secretary to prepare for a spending squeeze.
Treasury papers suggest the NHS is likely to see real term growth of less than 4% after 2007-8 - this compares with the 7% increase it has enjoyed since 1999.
Despite the huge year-on-year increases in funding, health trust managers told the Health Service Journal they were resorting to desperate measures to save money in this financial year.
Many laid the blame for the cash flow problems firmly at the door of the government.
Seven out of 10 said the NHS would not be facing such problems if it were not for "inflexible government targets".
And 99% said NHS reforms and changes to consultants' and GPs' contracts had had a big impact as they had not been costed effectively.
One in four of all trusts said they had made staff redundant, while 75% had brought in recruitment freezes.
Three quarters of trusts said they had brought in recruitment freezes
The Department of Health said improving financial management did not mean compromising patient care and that clinical needs were always paramount.
A spokesman said spending had only outstripped resources in a quarter of trusts and that 'turnaround teams' were helping them balance the books.
"There is more money than ever before in the NHS, and within two years, we will have brought NHS finances back into balance," he said.
"All the changes that are being made in the NHS are designed to achieve even better NHS services for patients."
The RCN, which has been tracking the level of NHS trust deficits and their impact on staff during 2005, said evidence from this year showed operations were being cancelled, beds closed and redundancies planned.
The chairwoman of the RCN Public Policy Committee, Barbara Tassa, said it was not acceptable that patients were suffering and nursing posts being lost because of the deficits.
She urged the government to step in now to address the problem.
"In October 2005 the RCN predicted that NHS deficits would hit £1 billion with up to three-thousand NHS posts lost.
"These predictions were dismissed by the government, yet we are now seeing a situation that is deteriorating. We have real concerns about the stability of NHS finances, especially in view of the roll-out of reforms such as Patient Choice and Payment by Results."
But the Department of Health dismissed the RCN figures as "back-of-an envelope" calculations.
Dr Gill Morgan, chief executive of the NHS Confederation which represents more than 90 per cent of NHS organisations, said the HSJ survey gave a crude picture of the overall situation.
"We must get this in proportion. The overall deficit is less than one per cent of the overall NHS budget.
"Over one million patients are treated in the NHS every single day and patients are now being seen and treated quicker than ever."
Shadow health secretary Andrew Lansley said Patricia Hewitt was in denial over the consequences of NHS financial deficits.
"It is time for her to take responsibility for the consequence of the government's polices," he insisted.