The seven imported cases include five people who arrived in the city from India, one from Indonesia and one from the Philippines.
None of the imported cases showed any symptoms.
The Centre for Health Protection (CHP) said 130 Covid infections had been recorded since March 21 – including 39 local cases, of which 11 had an unknown source.
It said people should avoid going out, dining out and having social contact, and strongly urged the elderly to stay at home as far as possible.
“Given that the situation of Covid-19 infection remains severe and that there is a continuous increase in the number of cases reported around the world, members of the public are strongly urged to avoid all non-essential travel outside Hong Kong,” the CHP said.
Hong Kong has recorded 11,508 confirmed cases of Covid-19 since the first infections were detected in the city in January 2020.