Hong Kong lacks a fallback industry, such as agriculture, for lower-income earners, an academic says. Such people may become jobless if the minimum wage law takes effect, he warns.
The city is trying to fix a statutory minimum wage as early as July.
As the decision looms, fast-food restaurant worker Mimi Leung, 47, is worried about her future.
'With no special skills, I'm unsure whether I can hold on to my job,' she says.
Leung is one of many workers who may be affected by the law, now under discussion by the Provisional Minimum Wage Commission.
Last month, the Census and Statistics Department found in a survey that nearly one in six, or 469,000, of the city's 2.78 million workers were paid less than the HK$33 an hour union groups are pushing for. More than 130,000 people earn less than the HK$24 that many business groups want.
The lowest hourly wages are in estate management, security and cleaning services, at an average of HK$27.60, while restaurant workers earn an average of HK$32.70.
Casey Wong Wing-sim, 19, left school after completing Form Five and now works at a fast-food restaurant for HK$22 an hour.
Wong looks forward to the legislation because she believes she will be better off. She says: 'I work very hard. I deserve to be reasonably rewarded.'
But, while most countries have a minimum wage, some experts argue that Hong Kong's unique circumstances make bringing one into law unsuitable.
On the mainland, minimum monthly and hourly wages are in place for full-time and part-time workers respectively. Provinces, municipalities and autonomous regions are allowed to fix their own minimum wages separate from the national standards.
For example, the minimum wage in Shenzhen is quite high, attracting skilled workers, but making it hard for the unskilled to find jobs.
It is a system that works, says Dr Mo Pak-hung, associate professor of economics at Baptist University, because mainland workers can fall back on farms. Hong Kong does not have such a safety net, he says.
'Employers will either look for the more productive to fill positions or cut costs. As a result, people will lose jobs,' Mo says. 'Those who are the least productive, for instance, the aged and disabled, will be hardest hit.'
Even if the minimum wage is set low initially, union power will nudge it higher in the long run - as has happened in other countries - putting a burden on the entire population, he says.
Mo argues that as wages rise over time, more people, including the young, will lose jobs.
This will result in increasing numbers of people relying on social security, leading to a larger social welfare burden for the community, the academic says.