The Public Health Agency currently defines a Covid-19 'cluster' as "two or more laboratory confirmed cases among individuals associated with a key setting" with the onset of the illness occurring within a 14-day period.
A key setting may be a workplace, educational establishment or similar type setting, the body explained.
However, cases detected within a household setting, explained the PHA, are not included within examples of 'clusters'.
"Covid-19 transmission risk is highest in a household setting, and it is to be anticipated that a significant number of linked cases within households will be identified by efficient contact tracing," said the health body.
"It is for this reason that household linked cases are not reported as clusters."
The PHA outlined its process for managing local coronavirus spikes, adding: "Clusters with increasing numbers, increasing complexity between cases, or sensitive issues are brought to the attention of the Health Protection Team.
"A rapid risk assessment of each cluster is then performed. Clusters may be observed, or merit formation of an Incident Management Team (IMT) or Outbreak Control Team (OCT)."
Urging the public to maintain social distancing and practice effective hand hygiene, the PHA advised anyone who is concerned they are displaying coronavirus symptoms to self-isolate and arrange a test as soon as possible.
For further information please visit www.pha.site/coronavirus