ALMOST two dozen coronavirus clusters have been identified in Northern Ireland since May.
The Public Health Agency said of the 23 pinpointed since May 25 when a test and trace programme went live, 11 clusters remain open.
Some 168 cases of Covid-19 have been associated with these clusters, with nine having had five or more cases associated with them.
Details emerged as the Department of Health's daily figures showed a jump in cases. A further 43 over the previous 24 hours brought the north's total since the pandemic began to 6,049.
No new deaths were recorded, leaving the total at 556.
In the Republic, five new deaths and 69 more cases were recorded, as the government warned of a very "delicate position".
The public was urged to "stall" a spike in infection as it emerged the number of suspected cases in ICU doubled over the last week.
The PHA defines a cluster as two or more laboratory-confirmed cases of Covid-19 among individuals associated with a key setting, with illness onset dates within a 14-day period.
Key settings include workplaces, retail or hospitality premises, domestic gatherings and sporting settings, with the transmission risk highest in a household.
Since July, the average number of close contacts linked to cases in the north has more than doubled.
The agency said this may be attributed to the gradual easing of lockdown measures, but may also be explained by the relaxing of attitudes to social distancing.
Dr Gerry Waldron, head of health protection at the PHA, said: "Clusters are managed through the contact tracing programme, 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.
"In the past seven days, five clusters have been identified. Thirty-five cases have been associated with these clusters, with 239 close contacts.
"This should act as a timely reminder that we must not become complacent - coronavirus remains in circulation and we have seen an increase in cases in recent weeks. It is therefore essential that we remember the key advice to help keep ourselves and those around us safe.
"Maintain social distancing, wash your hands regularly, and get tested if you display any symptoms of coronavirus."
The Department of Health has also revealed that the 'R' number is now "highly likely" to be above one in Northern Ireland.
R represents the number of individuals who, on average, will be infected by a person with the virus.
The current estimate for the R value is between 0.8 and 1.8.
A spokeswoman for the Department of Health said while community transmission remains low in Northern Ireland, the number of positive tests per day has increased three-fold from early July.
Chief scientific adviser Professor Ian Young said: "The most recent data for Northern Ireland underlines the need for continued vigilance.
"There are five key steps each of us can take to keep ourselves and others safe - rigorously maintain social distancing; wash our hands well and often; wear face coverings in enclosed spaces where social distancing is difficult; co-operate fully with the Test, Trace and Protect programme, and download the Stop Covid NI app."
