The health service ‘looks like a supertanker heading for an iceberg’, warned the head of the NHS Confederation during a Manchester conference.
Almost half of the 252 NHS leaders in Manchester fear that growing financial pressures will damage patients' quality of care.
The survery found 47% said the health services provided is in a ‘very serious’ state and that they are deeply concerned about the NHS’ future.
Mike Farrar, chief executive of the confederation, said: "Despite huge efforts to maintain standards of patient care in the current financial year, healthcare leaders are deeply concerned about the storm clouds that are gathering around the NHS.
"Our survey shows that many NHS leaders see finances getting worse and that this is already having a growing impact on their patients.
“In response, they are cutting costs in the short term but they know that much more radical solutions are the only answer in the long run.
"Frankly, without action on the way we provide health and social care, the NHS looks like a supertanker heading for an iceberg.
“The danger is clearly in view and looming ever-larger. We know what needs to happen. But are we going to be able to take the assertive action needed in time?
"NHS leaders surveyed are clearly worried about standards of care. They associate this with the tight financial position, the even tighter financial position faced by local authorities, the distracting effect of the reforms, the time that it will take the reforms to bed in, and the chronic failure of political leadership to secure the public support for the changes they know are needed.
"It is clear that what the NHS desperately needs is public support for planned change to services.
He added: "But politicians have consistently failed over many years at national and local level to put the long-term interests of their population's health above their short-term electoral interests.
"The NHS will get on and do its absolute utmost to make things work for patients. But we do not have the luxury of time if we are going to make the right changes to services.
“Health and social care leaders must come together now and speak about these issues with one loud, strong voice.
"I genuinely believe we can achieve a better and sustainable NHS but as the survey suggests, we face a mighty struggle unless we take the necessary steps as soon as possible."
Health Secretary Andrew Lansley, who will also address the conference, said: "We know that the NHS is performing extremely well for patients, with waiting times and hospital-acquired infections low and patient experience of care high.
"But there are financial pressures; as nearly half of the respondents to the NHS Confederation's survey made clear, they are very serious but not the most they have experienced.
"Recognising this, we have committed to investing an extra £12.5 billion in the NHS and led a programme of quality-led savings for reinvestment in services, which is on track.
"The NHS needs to change to match the needs of a changing population. We will not shy away from difficult decisions involved in that. But any local plans must be led by the need to use resources more effectively to support and improve services and the quality of NHS care.
"The Confederation survey shows leadership to deliver integrated, innovative services is the priority, which is exactly where our reforms are taking us."
Katherine Murphy, chief executive of the Patients Association said: "This survey confirms what everybody inside the health and social care system is already saying – the next decade is likely to be the most challenging one in the history of the NHS.
"Treatments are being rationed, waiting times for elective procedures are going up and patients continue to be treated poorly on our hospital wards.
"All of this, and the £20 billion of efficiency savings haven't even started to bite yet. As Mike Farrar rightly says, changes need to be made now that will protect patients, and the NHS, for the long term."