Tens of thousands of NHS workers could be sacked and thousands of hospital beds lost under plans outlined by strategic health authorities, it was reported.
The plans could also see procedures such as hip replacements scrapped and patients encouraged to email doctors rather than visit surgeries, according to the Daily Telegraph.
Proposals were drawn up by the 10 English strategic health authorities for productivity and efficiency savings.
The plans come after NHS chief executive Sir David Nicholson spoke of the need to make between £15 and £20 billion in productivity efficiency savings over three years. The Department of Health said it was "committed to protecting the NHS frontline". But the Telegraph has seen documents from SHAs which show how the cuts could fall on hospital services.
The newspaper said that in the South East Coast region, which covers Surrey, Kent and Sussex, up to £1.6billion must be saved. A document marked "restricted" and circulated among SHA board members suggests 10,000 or more of the region's 100,000 NHS workers may lose their jobs.
It stated: "The new financial environment demands that the trend in workforce growth must be reversed." It said staffing in the acute sector, covering hospitals, "can be expected to decline faster and further" than elsewhere.
A spokesman for the South East Coast SHA told the newspaper the document was a discussion paper and not a final plan. The Telegraph also said that in London, which faces £5 billion in cuts, documents show managers believe up to £2 billion can be saved from community care budgets, which cover GPs' surgeries.
It said this would include "changing how patients get in contact with and receive services, such as through greater use of the internet and email". A Department of Health spokesman said: "We are committed to protecting the NHS frontline. All the efficiencies in the frontline will be reinvested in the NHS.
"To ensure that the quality of NHS services continues to improve, service must be more productive. Better designed services can deliver both better quality and value for money. Service change proposals must demonstrate a strong clinical case for change, promoting better outcomes for patients.
"We will be clear with trusts that they must not make short-term cuts that harm patient care. Service change is important to drive through our reforms and must be guided by the need to improve quality for patients and secure best value for taxpayers' investment. Right now we are confident, based on good financial management over the last few years, that the NHS can continue to improve."
