Royal College of Nursing (RCN) director Janet Davies told the BBC the findings were "very concerning but not surprising - we have been hearing about this for some time from nurses".
She added: "What we are finding is the pressures, particularly in hospitals and community areas, are getting greater as we have got more patients who are sicker coming through the system.
"We are seeing nursing posts frozen or cut in order to try and balance the books, it's obviously something we have been looking at for some time."
More top news
Choir wins public vote, while judges pick dancers ahead of 12-year-old singer-songwriter Henry Gallagher.
The hunt for murder suspect Jed Allen has ended after police found his body two days after discovering his mother, stepdad and sister dead.
A woman who had been searching for her mother for more than 10 years has been reunited with her after posting an appeal on social media.