Surge testing for the Indian Covid variant could be introduced as soon as today, after multiple outbreaks were reported in the UK.
The strain is expected to be elevated to a "variant of concern" after infections were found in several areas of England, according to reports.
Cases of the variant have been detected in schools, care homes and places of worship in the North West, London and the East Midlands, according to Channel 4 News.
These infections have largely been linked to travel, it is claimed. Indian is currently facing a new coronavirus crisis after a huge surge in infections put a strained health system under pressure.
Channel 4 News said it is "highly likely" the strain will be declared a "variant of concern" on Friday, although cases still remain relatively low.
Such a change can mean an escalation in response from Public Health England (PHE), including ordering surge testing.
The strain - B1617.2 - is one of three related variants first seen in India which have been detected in the UK and designated "under investigation" by PHE. The others are B1617.1 and B1617.3.
According to Channel 4 News, there have been at least 48 clusters of the first variant.
PHE said updates on the number of cases due to be released on Thursday have been delayed due to "processing issues".
According to internal documents from PHE, dated to May 5 and seen by The Guardian, the ongoing risk to public health from the variant subtype B1617.2 is "high".
Dr Deepti Gurdasani, a clinical epidemiologist and senior lecturer at Queen Mary University of London, told The Guardian that "at the current doubling rate (B1617.2) could easily become dominant in London by the end of May or early June".
It comes as seven confirmed cases of the variant were detected in Northern Ireland - the first discovered in the region.
Chief medical officer Dr Michael McBride said the news was "not entirely unexpected" and that plans were in place "for such an eventuality".
Health experts have said they "haven't seen any hint" of a current Covid variant that can fully evade the effectiveness of vaccines.
The Department of Health and Social Care and PHE have been contacted for comment.