Doctors in Northern Ireland have expressed concern at the increasing number of patients and hospital visitors who are not wearing masks.
The British Medical Association in Northern Ireland has said there were also more people refusing to take Covid-19 tests before coming for hospital appointments or when attending emergency departments.
Dr David Farren, deputy chair of BMA Northern Ireland's consultants committee, said staff were facing aggressive behaviour when they challenged non-compliance.
"We are seeing an increasing number of patients who are refusing to wear face coverings, which remain a requirement in government-owned buildings, and are refusing to have a Covid test when attending hospital for assessment or admission," he said.
"This is extremely challenging for medical staff because we then have to treat these patients as if they have Covid, but we cannot mix them with other Covid patients as that would risk actually giving them Covid if they don't have it."
It comes as 1,306 new cases of Covid-19 were reported in Northern Ireland today, along with three further deaths.
There were 334 Covid-19 patients in hospital, including 47 in intensive care.
Dr Farren said that patients refusing to wear face coverings is putting additional demand on hospital beds at a time when the health service is already under "significant pressure".
"We have also had increasing reports of aggressive behaviour towards our staff when challenging those who refuse to wear masks without a medical exemption," he said.
"I would urge anyone attending hospital who can wear a mask to please do so to protect themselves and others.
"Staff will challenge this if you do not, and it is unacceptable for this to be met with aggression.
"Testing before assessment or admission is equally important.
"I fully acknowledge that the swabs are not pleasant, but it is essential that anyone who is coming for assessment or admission to hospital is tested if we are to prevent spread of Covid-19 within our hospitals."`
Dr Alan Stout from the BMA GP committee said GPs had worked extremely hard to keep their premises open and free of Covid.
"Increasingly we are being challenged by patients who simply don't want to wear a mask, not because they have a valid exemption.
"Our staff and GPs are just trying to do their job and ensure everyone's safety. Having to make special arrangements for people refusing to wear a mask is extremely difficult and time-consuming and takes staff away from other tasks that need completing.
"We have some very vulnerable patients attending our surgeries and it is vital that we do everything we can to ensure their safety and confidence."
Three further deaths of patients who had tested positive for Covid-19 were reported in Northern Ireland yesterday, with another 1,294 new confirmed cases of the virus.
