The flight ban, which will be in place until September 16, was triggered after four helpers who flew in two days ago tested positive for Covid-19, and another passenger failed to comply with the entry requirements.
The Centre for Health Protection (CHP) said the four helpers, all infected with the potentially more contagious L452R mutant strain, were the only new coronavirus infections reported on Friday.
The four women, aged between 32 and 45, were all earlier fully vaccinated with either the Sinovac or BioNTech jabs. Three of them took their shots in Hong Kong, and the other one in the Philippines.
Separately, the centre deleted five previously confirmed cases, saying traces of the virus found in their specimens were compatible with the vaccine strain.
The centre said one of the five patients had received a Covid vaccine at a community inoculation centre, while the remaining four had visited the same private clinic which provided Covid vaccinations.
The CHP said it had been conducting checks on all local cases recorded since the vaccination programme started in February, in view of recent positive samples which turned out to be contaminated by the vaccine strain.
The total number of Covid cases in Hong Kong now stands at 12,112.