Nurses say staffing levels are poor at Northern Ireland's five health trusts, according to research.
A survey of 2,000 nurses found that almost 60% perceived problems with staffing levels and a significant number claimed they are being stretched to the limit.
Anne Speed, a spokeswoman for the public service union Unison which carried out the study, said: "For many working within the health sector, this won't be a revelation, for them it is simply reflective of the ongoing cuts that are being made to nursing jobs across Northern Ireland. "
She continued: "Since December 2009, the nursing workforce has decreased by 2% with a further 500 posts expected to be cut by 2013. The number of district nurses has also fallen by 8% over the past two years.
"It is patient care that is suffering as a result of these cuts. In Unison's 2010 report Care in the Balance it outlines that a minimum nurse to patient ratio saves lives and results in better patient care. Yet, this survey shows that 85% of nurses across all trusts and bands state that their workload is 'heavier' than three years ago."
The study found that nurses, particularly in the Belfast and Northern Trust areas, believed their workloads are significantly higher than three years ago.
Last week it emerged that a patient had died after a 22-hour wait on a trolley at Antrim accident and emergency while six months ago an elderly man died in similar circumstances at Belfast's Royal Victoria Hospital.
Ms Speed added: "Over the past three years staff shortages, combined with changed skill or grade mix, has had a major impact, with fewer nurses treating more patients. Nursing staff are stretched to the limit. Whilst patient dependency has increased, staffing levels on the wards have not matched this."
Nurses also raised concerns about low and deteriorating morale, difficulties in being able to access additional training and a high proportion of those in bands two or three and seven said they were likely to leave their employment because of the staffing concerns.
Unison representatives are expected to raise the findings of their study Stretched on the Front Line - Who Really Cares? with Stormont politicians within the coming weeks.