Significant numbers of nurses, including some in the most high-risk environments, have felt pressure to work with inadequate protection, a union has claimed.
High-risk environments include areas where patients with or suspected of having Covid-19 were being treated on ventilators.
Nearly half of those surveyed from Northern Ireland (42%) helping patients in such areas reported being asked to reuse items of protective equipment marked single-use by manufacturers. Of those treating Covid-19 patients elsewhere, over a third (38%) said they were being asked to reuse.
Pat Cullen, director of the Royal College of Nursing (RCN) in Northern Ireland, said: "We all know that nursing staff have been under enormous pressure during this pandemic.
"However, it is shocking to find that nurses are feeling pressurised to work without the protection they need."
The findings are from a survey conducted by the RCN to provide a snapshot of PPE shortages over the Easter weekend.
Health chiefs here say they have secured millions of items from international and local suppliers.
Ms Cullen added: "This is an anxious and worrying time for staff, and they must have the reassurance that they can do their jobs with all of the equipment necessary.
"Time and time again we have been on record as saying this.
"It is very disappointing to find that there are still problems.
"Nurses carry out the majority of direct patient care and, while we acknowledge that these are extremely challenging times, we must resolve these issues. If we don't, this will inevitably lead to further problems."
The survey of local nursing staff said:
Meanwhile, the NI Blood Transfusion Service came under fire from trade union Unison, which claimed front line staff in the vital service were concerned that they were not being given an adequate level of PPE to do their job safely during the Covid-19 pandemic.
Unison's Marianne Buick said: "Staff working with blood donors feel they should have masks and visors to provide reassurance and protect both the public and the transfusion staff.
"What I want for our membership is that they are provided with the proper PPE to enable them to have confidence in doing their job. Not just for them, but also to reassure the blood donors who want to help the NHS during this crisis."
Matt Gillespie of the NI Blood Transfusion service said that his organisation had been following World Health Organisation guidelines on PPE provision, but was moving to address the staff concerns.
"We will be meeting the union early next week to revise our risk assessment and see what measures we can put in place to alleviate the stress and fears that staff have," he said.