The Centre for Health Protection (CHP) said in a statement published on Wednesday morning that the two women – aged 46 and 38 – live in Kornhill in Quarry Bay and Royalton in Pok Fu Lam respectively.
The two were reported as preliminary positive cases on Tuesday, and further analyses found that both carried the N501Y and E484K mutant strains.
One of them was also said to have received her first BioNTech vaccine jab on April 18.
The CHP said it would transfer all asymptomatic residents to quarantine centres, while those with symptoms would be sent to hospital.
Around 230 units at Kornhill and 30 units at Royalton were affected by the government’s move, which came hot on the heels of ambush lockdowns of the blocks, with residents made to undergo mandatory tests.
Some Kornhill residents told RTHK they were concerned about the possibility of Covid-19 being transmitted in the neighbourhood.
“We have done our best to avoid being infected and everybody is very careful in the area,” one woman said.
“Of course we’re very concerned because this is a variant, but we need to just take care of ourselves, maintain proper hygiene, that’s all,” another woman told RTHK.