This is the first case of the new variant to be reported in the island country, Xinhua reported.
Samaraweera said the infected patient had arrived in the country a week or two ago and further investigations were underway.
Till date, Sri Lanka has detected over 49,000 positive Covid-19 patients as the country is in the midst of a second wave of the pandemic.
According to the Health Ministry, out of 49,537 patients detected since March, 42,621 patients have recovered and been discharged from hospitals bringing down the active patient count to 6,627.
It said that so far 244 patients have died of the virus.