Labour may be trying to target hospital cutbacks in areas where rival parties have seats, the Conservatives claim.
Accident and emergency departments are among those facing closure
The Tories have seen leaked e-mails detailing meetings between ministers and Labour party officials.
Shadow health secretary Andrew Lansley said there also seemed to be a deliberate attempt to cut fewer services in Labour constituencies.
Downing Street denied changes were politically motivated, insisting they were what was best for local people.
Tony Blair's official spokesman said: "The restructuring is based on an analysis of what services are needed at a local level."
The claims follow news an Accident and Emergency unit in a key marginal constituency is to be axed in favour of an "urgent care centre" dealing with less serious casualties.
The provisional decision to scrap Rochdale Infirmary's A&E unit was taken by a joint committee of Primary Care Trusts in the area.
Rochdale Labour Party has been hoping to oust Liberal Democrat MP Paul Rowen at the next election. He snatched the seat from Labour in 2005 with a majority of only 442 votes.
The Rochdale decision is the first since NHS chief executive David Nicholson unveiled plans to concentrate key NHS services at fewer hospitals - a plan which could include around 60 such "reconfigurations".
Labour Party chairman Hazel Blears met Health Secretary Patricia Hewitt on 3 July to talk about hospital closures and other matters, leaked e-mails seen by the BBC reveal.
The e-mails also refer to "heat maps" - Whitehall jargon for maps showing areas where public concern about hospital closures is running high.
But officials deny press reports "heat maps" show areas where Labour could lose seats.
Andrew Lansley, for the Tories, said he had not seen the minutes of Ms Blears' meeting with health ministers but added "I can see what is happening and it really makes me angry".
"There are difficult decisions to be made in the NHS and they are the responsibility of Labour because the financial mismanagement of the unprecedented resources going into the NHS has badly let down NHS staff, and the patients and the public.
"And those difficult decisions should be openly arrived at," he told BBC Radio 4's Today programme.
He said he did not think Mr Nicholson and staff at strategic health authorities, which make the decisions about local services, were "complicit" in politically motivated health closures.
But he added: "I think ministers are telling officials what to do and officials, unfortunately when ministers tell them things just go off and do it."
He said the NHS should be more independent and called for an end to "sham" consultations in which the public were not given the full facts.
And he urged Labour to stop using the NHS as a "political football".
Steve Webb, for the Liberal Democrats, said: "No one doubts that there must be change in the health service, but people will be outraged to find out this is being planned around the jobs of Labour MPs.
"The NHS is owned by all of us. It is not a plaything of the Labour party."
Health Minister Rosie Winterton insisted decisions were being made with patients in mind and there had been no political pressure on the "reconfiguration" of local health services.
"Very often when we're talking about these reconfigurations it is about saying what is the best way of delivering care," she told the Today programme.
She said in areas like cancer specialisms it can be effective to have experts who deal with a particular type in one place.
Hazel Blears had met health ministers and officials, added Miss Winterton, but had been "quite properly" looking at the "political dimensions" of health policy, such as whether manifesto commitments were being delivered.