NHS England, which needs to find £22bn in efficiency savings by 2020-21, said reorganizing local services is essential to improve patient care. Suggestions have been leaked from a sustainability and transformation plans (STPs) which propose ward closures, cuts in bed numbers and changes to A&E and GP care in 44 areas.
The director of the campaign group 38 Degrees, said the plans had received very little public or political scrutiny "These plans are due to be signed off this October - a matter of weeks away".
"A key concern is why it hasn't been this transparent up until now.
The STPs are being drawn up by local health and social care leaders, although many remain unpublished. They were asked to find potential savings and efficiencies at the end of last year to meet financial targets set out by the former Chancellor George Osborne and NHS England head Simon Stevens.
38 Degrees uncovered many unreported draft STPs, including plans for the closure of an A&E in the Black Country and the merging of two of the area's three district general hospitals and the closure of one site.
In the area of Leicester, Leicestershire and Rutland, there are plans to close acute services from one of three hospitals.
There are also plans to put GP surgeries under "review" because of a shortage of funding.
A draft plan circulating among NHS managers in West Yorkshire reveals proposals to close the equivalent of five wards in the Leeds Teaching Hospitals Trust.
Nigel Edwards the head of the Nuffield Trust said: "The speed of the process to shape these plans has meant that they have so far not been very visible". Mr Edwards said in some cases large numbers of patients would have to be shifted into community settings to make room for growing demand, while in others up to 20% of beds may be closed. The role of community hospitals is being questioned and the number of mental health inpatient sites could be reduced, he added.
Sally Gainsbury, senior policy analyst with the trust, said many of the plans at the moment appeared to be proposing shifting or shutting services.
"Our research finds that, in a lot of these kinds of reconfigurations, you don't save very much money - all that happens is the patient has to go to the next hospital down the road.
"They're more inconvenienced... but it rarely saves the money that's needed."
An NHS England spokesman said, "Proposals are at a draft stage but we expect all local leaders to be talking to the public and stakeholders regularly - it is vital that people are able to shape the future of their local services. "No changes to the services people currently receive will be made without local engagement and, where required, consultation."
If you feel that your services are going to close or be shifted, and you or someone you know may be affected by these proposed changes, Don't stay silent, please,