According to data from the group, about half of the 874 units have been vacant for over a year, while 32 percent have been vacant for at least two years.

About a hundred of the units are stigmatised properties in which murders or suicides have occurred. Units are also inaccessible for disabled residents.

The concern group has recommended that the government make use of these public housing units as transitional housing units to temporarily accommodate low-income residents and those affected by government clearance operations.

The average waiting time for public housing rises to a 23-year high of 6.1 years, according to data from the Housing Authority.

Experts expect the average waiting time to increase throughout the year, depending on chief executive-elect John Lee Ka-chiu’s efforts to increase and speed up housing and land supply — an issue that he has highlighted in his manifesto as the main policy focus.