Only four recruitment agencies for domestic helpers lost their licences last year despite a record total of complaints against them.
The findings by the South China Morning Post prompted calls for a self-regulating industry body to be set up to help protect foreign domestic workers.
The facts emerged as the first group of 19 Myanmese helpers arrived in Hong Kong yesterday. Concern groups said the government should use the opportunity to clean up the industry.
Elizabeth Tang Yin-ngor, general secretary of the International Domestic Workers Federation, said of the figures: "I am shocked. But I have always been dissatisfied with the supervision of the Labour Department. It needs to seriously beef up its efforts."
The department said there were 1,253 licensed employment agencies for foreign helpers at the end of last year. Four licences were not renewed, with the reasons given including the overcharging of workers and illegal practices. One agency's licence was revoked in 2010, three in 2011 and two in 2012.
But the Asian Migrants' Co-ordinating Body said that for Filipino domestic helpers alone, a record 8,000 complaints of overcharging were filed to their consulate in Hong Kong last year.
Local laws allow agencies to charge helpers 10 per cent of their first month's salary, or HK$401, but many helpers reported being charged as much as HK$20,000.
It is unclear how many of these cases were referred to the department. And there are no similar figures available for Indonesian helpers. But with Indonesian and Filipino helpers each making up about half of the city's 320,000 domestic workers, the number of complaints by Indonesian helpers is also likely to be in the thousands.
Tang said the department should have investigated these cases and dished out punishment, even if the helpers did not complain directly. "Exploitation is so rampant, there is no way the department cannot manage to find out about it," she said.
Tang said the department should arrange briefings for workers new to the city, telling them about labour rules and to whom they can go for help.
Teresa Liu Tsui-lan, vice-chairwoman of the General Chamber of Manpower Agencies, said a self-regulatory body for the industry, similar to the Travel Industry Council, should be set up. "If you're not a member of the council, then you don't get a licence," she said.
Liberal Party lawmaker Felix Chung Kwok-pan, who has talked to officials from Myanmar's labour ministry about the possibility of bringing 10,000 Myanmese helpers a year to Hong Kong, said any agencies found guilty of malpractice should get "points" deducted.
Once the self-regulatory body had deducted all their points, the licence should be revoked.
A spokesman for the Labour Department said: "We do not allow abuse in any form." He said the Myanmese helpers would enjoy the same legal protection and rights as local employees.