Health officials said Hong Kong recorded 4,979 new Covid infections on Sunday, one day after the daily caseload topped 5,000.
Of the latest cases, 4,764 were local infections and 215 were imported ones.
Authorities said a girl, 5, remained in critical condition in Tuen Mun Hospital after contracting the coronavirus.
Her sister, 11, has also tested positive for Covid.
"We understand that the older sister has a bit of sore throat and she's in stable condition in Tuen Mun Hospital," said Gladys Kwan, a chief manager at the Hospital Authority.
She added that the authorities are still investigating the source of infection for the sisters, and could not confirm if one had passed the virus to the other.
Health officials said a total of 1,690 Covid patients remained in hospital, 10 of them in intensive care.
Three more coronavirus patients died. They were aged between 80 and 89, and only one of them had been vaccinated against Covid-19.
Meanwhile, the Centre for Health Protection revised Saturday's figures, with 25 of the day's local cases re-classified as imported ones. The total number of infections remained unchanged at 5,308.
General Covid-19 situation: https://www.coronavirus.gov.hk/eng/
Community Clinics for Covid-19 patients: https://bit.ly/3a4BZFE
RAT reporting platform: https://www.chp.gov.hk/ratp/
Vaccination programme: https://www.covidvaccine.gov.hk/sen/
Vaccination pass scheme: https://www.coronavirus.gov.hk/eng/vaccine-pass.html
Hotline for Covid-positive patients: 1836 115