More than half of the local labour force work more than 44 hours a week, a survey has found.
In particular, nearly one in five respondents put in more than 52 hours at work each week.
The findings signalled a need for the city to introduce a law on working hours as soon as possible, a moderate pan-democratic political group said.
"Family disputes arise very easily in these cases because family members do not have much time to spend with one another," lawmaker Leung Yiu-chung, of the Neighbourhood and Workers Service Centre, said yesterday.
"The government always stresses the importance of harmonious family ties, but how can that happen when it is so slow in standardising working hours?"
The Labour Department defines standard working hours as the normal number of hours an employee should work on a regular basis, beyond which overtime wages are payable.
The centre wants working hours capped at 44 a week, with workers getting 1.5 times their normal wages for any extra time they put in. Bosses say a law may hurt competitiveness and worsen the labour shortage.
The centre polled 287 employees from sectors including finance, retail and restaurants from March to this month.
It found that 36 per cent of them put in 44 to 52 hours of work a week; 19 per cent worked over 52 hours. Another 31 per cent worked 18 to 44 hours, while 14 per cent did fewer than 18 hours.
Almost 90 per cent supported standardising work hours, with 4 per cent against it.
Leung said some employees feared losing their jobs if business costs rose as a result of the law. A 2012 government study showed employers would have to pay up to HK$55.2 billion more a year in wages if a law was introduced.
A 24-member special committee, set up last year to look into the pros and cons of such a law, has commissioned a consultancy to poll about 10,000 workers.
Sum Chik-wing, a security guard in a factory building, gets paid the minimum hourly wage of HK$30. "I work 12 hours a day, 72 hours a week. Where do I get the time to be with my family? I don't even have enough time to rest," he said.