The two imported cases – an 18-year-old man from the UK and a 34-year-old woman from Bangladesh – were asymptomatic.
Both arrived on June 28, with the 18-year-old arriving on flight BA031 while the 34-year-old arrived on flight QR818. Officials said both carried the L452R mutant strain.
The Centre for Health Protection (CHP) also said they had been notified by UK health authorities that two people who had departed from Hong Kong on June 18 had tested positive for Covid-19.
The confirmed cases, a 43-year-old woman and a 5-year-old boy, left Hong Kong on flight CX251, and samples collected from them on June 21 came back positive for Covid-19. They are asymptomatic.
The CHP said they are following up on the cases with the UK health authority, and epidemiological investigations are ongoing.
It said that the pair’s place of residence, Horizon Suites in Ma On Shan, will be put under a compulsory testing notice.
“Any person who had been present at the building for more than two hours during the period from June 5 to 30, 2021, has to undergo testing on or before July 2,” the CHP said.
Over the past fortnight, Hong Kong has recorded 41 cases – 39 imported infections, and two import-related cases.