The issues will be key themes of the Royal College of Nursing's annual conference in Liverpool.
RCN leader Peter Carter has said nurses were being pushed to the limit, working extra hard to keep services going.
A Department of Health spokesman said an extra £11.5bn of funding was being ploughed into the NHS.
The Health Secretary, Andrew Lansley, is not expected to give a speech at the conference but will meet delegates.
It is understood he is attending the conference as part of the government's "listening exercise" over its shake-up of the health service.
Dr Carter told the BBC he accepted the NHS had to save billions of pounds over the next four years but said it was wrong to cut front line staff.
"We are seeing not just nurses, but cleaners, doctors and speech therapists' posts being cut. That is the reality," he said.
Dr Carter pointed out that the National Audit Office reported recently that £0.5bn could be save by making the "chaotic" system of purchasing for the NHS more efficient.
He said: "If you cut nursing staff that will ultimately cost more money and reduce standards of care."
Under the coalition government's plans, GPs will be given control of much of the NHS budget, while greater competition will be encouraged with the private sector.
A bill is already going through Parliament to pave the way for the changes, but the government was forced last week to effectively re-open the consultation process after mounting criticism of its proposals.E-mail poll
The four-day conference, which will be attended by thousands of nurses, is likely to prove to be a testing moment for ministers battling to convince the medical profession and wider public that its reforms are right.Continue reading the main story
The NHS is going through considerable upheaval at the moment... we are concerned at the NHS's ability to cope”End Quote Peter Carter Royal College of Nursing The union has said it supports the basic principles, but was one of a number of organisations to raise concerns about the pace of change, lack of accountability and involvement of the private sector.
Ahead of the conference, the RCN released research showing that some nurses were being forced to go without breaks and work beyond their contracted hours because of the demands being placed on them.
The union e-mailed 100,000 nurses about their working conditions. The response rate was low - just over 2,000 took part - but the union said it still showed a service under strain.
Many raised concerns about staffing levels, with most respondents saying they were working extra hours.
Some said they missed meal times and breaks, with a number saying they sometimes did not even have time to get a drink of water.
The RCN has long been campaigning about what it sees as a cull of jobs in the NHS as trusts tighten their belts.
While the health service is getting small rises in its budget, many argue that costs from issues such as the ageing population and lifestyle factors including obesity outstrip these increases.
Dr Carter said the situation meant nurses were at risk of "burn out", which would harm patient care and undermine attempts to reform the health service as nurses were the "oil in the engine" of the NHS.
He added: "The NHS is going through considerable upheaval at the moment. Coupled with increasing demands on the health service, including from a rise in people with long-term conditions, we are concerned at the NHS's ability to cope.
"Trusts need to make sure they have the right numbers and balance of staff to deal with this."
A Department of Health spokesman said: "We have 2,677 more nurses now than we did in 2009, and have committed to employing an extra 4,200 health visitors to support children and families in the crucial early weeks and years.
"The government is getting rid of bureaucracy and clinically unjustified targets so that nurses are freed up to do what they do best - taking care of patients.
"We are also protecting the NHS, ploughing in an extra £11.5bn of funding. Any efficiency savings must not impact adversely on patient care."
This post was made using the Auto Blogging Software from WebMagnates.org This line will not appear when posts are made after activating the software to full version.