The number of those who live alone has risen almost 40 per cent in the past 10 years, with elderly women and middle-aged people contributing the most to the sharp increase, government figures show.
In 2001, fewer than 290,000 people lived alone, but the number rose to more than 400,000 in 2011, the Census and Statistics Department revealed, attributing the change to the post-war baby boom and the growing number of unmarried people in the city.
Those aged between 45 and 64 doubled from 73,000 to more than 150,000 in the past decade; and the proportion of women in that age group who lived alone rose from 4 per cent to 6 per cent, while that of men rose from 6 per cent to 7 per cent.
Single-person households in the city also increased by more than 50 per cent in women over the age of 65 in the past ten years - from less than 49,000 in 2001 to almost 74,000 in 2011.
Seventy-six per cent of the elderly women who lived alone were widowed, while of men in the same category, only 30 per cent of them were widowers.
"This may be attributed to the longer life expectancy of women," the department said.
The number of men aged between 25 and 44 living alone has however dropped from 73,000 to 66,400 over the decade.
The department said it was due to a decrease in population size. The number of men below 25 years old living by themselves has also decreased by 34 per cent to 3,820 in 2011.
Meanwhile, almost 30 per cent of the middle-aged men in single-person households were married, compared with only 11 per cent of the women.
This could be because of the number of men married to mainland women who were waiting for approval to settle down in the city, the report suggested.
Nearly a quarter of the people living alone were associate professionals, the report said. Fifteen per cent of them were managers and administrators, and 14 per cent were in elementary occupations.
The middle-aged people who lived alone, especially the women, were generally better educated than the overall population, with about half of them having secondary education and a quarter having post-secondary qualifications, the report said.