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.
If you have a story or want to send a photo or video to us please contact the Derry Now editorial team on 028 7129 6600 for Derry City stories Or 028 7774 3970 for County Derry stories. Or you can email firstname.lastname@example.org or email@example.com at any time.
Subscribe or register today to discover more from Derrynow.com
Buy the e-paper of the Derry News and the County Derry Post here for instant access to Derry's premier news titles.
Keep up with the latest news from Derry with our daily newsletter featuring the most important stories of the day delivered to your inbox every evening at 5pm.