The Western Trust is asking people not to visit patients in any of its hospitals.
The appeal comes amid ongoing concern about the potential spread of the coronavirus.
A Western Trust spokesperson today said they were taking 'necessary precautions' to protect patients and staff.
"We are asking the public not to visit patients in our hospitals and community facilities unless absolutely essential," the spokesperson said.
"Where possible, please attend your appointment on your own."
Four new cases of coronavirus were today confirmed by the Department of Health, bringing the total number of cases in Northern Ireland to 16.
All four cases are adults and one case involved travel from northern Italy.
Three of the cases can be traced to a previously reported case that involved recent travel to northern Italy.
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