The announcement came a day after expert committees under the Centre for Health Protection recommended the move, noting that most of those who have died in the latest wave of infections were over the age of 60.
People in this age group can get a fourth dose as long as three months have passed since their third jab.
Civil Service Secretary Patrick Nip, who is in charge of the city’s vaccination drive, said from April 14, the over 60s will also be able to make bookings online for a fourth jab.
He noted, however, that more than 1.7 million people who are eligible for a third dose of Covid vaccine have yet to do so.
The government experts say there is no need at this stage for younger people to get a fourth jab and they can wait until later this year when second generation or so-called “Omicron-matched vaccines” are likely to become available.