A cluster of Covid-19 cases has been linked to a social gathering in a private/residential setting, it has emerged.
The Public Health Agency said they had been traced to the Limavady area.
In a statement, the agency said: "Testing and contact tracing is being conducted to identify people who may be potentially affected to help prevent any further spread.
"With lockdown restrictions being eased this type of occurrence is to be expected, which is why the Test, Trace and Protect programme is in place.
"At present anyone who tests positive for COVID-19 in Northern Ireland will be contacted by the contact tracing team to be given advice on what to do about managing symptoms and of the need to self-isolate to prevent any wider spread of the virus.
"They will also be asked who they have been in contact with so that we can follow up with those individuals to give them advice to help prevent the further spread of infection.
"Contact tracing is an established method to help prevent the further spread of infections such as COVID-19, and we are using this approach to target potential clusters which could spark new outbreaks.
"If the team identifies a potential cluster or outbreak this will be reported through the PHA’s normal outbreak management channels and the appropriate infection control advice/actions carried out."
It added: "PHA will continue to monitor all cases of COVID-19, look for trends and linked cases and where we need to advise or inform the public of any increased risk to public health we will do so in a timely manner.
"We will not comment on individual cases as this could lead to people being identified and deter others with symptoms coming forward to be tested. We would ask everyone to be mindful of this risk.
"This virus has the potential to make its presence felt in any district. Everyone should act on the basis that it might potentially be in their neighbourhood right now. That’s why following the public health advice on regular hand washing and maintaining a social distance of two metres remains vitally important.
"If anyone is concerned that they are experiencing any of the symptoms of coronavirus, they must self-isolate and arrange a test as soon as possible. For further information on the virus, its symptoms and how to book a test, visit www.pha.site/coronavirus.
"We must be aware that COVID-19 is still a threat and we need everyone to play their part in helping to stop the virus spreading."
