A total of 521 companies with unfair employment practices were warned or sanctioned by the Manpower Ministry (MOM) from 2013 to 2017.
Of these, 58 per cent received warnings, while 42 per cent faced more difficulty when applying for foreign work passes.
"So you can see that there is action being taken, and certainly we have to be fair to both employees and employers to make sure that the cases are dealt with fairly," said Minister of State for Manpower Zaqy Mohamad in Parliament yesterday.
He was replying to Nominated MP Walter Theseira, who asked whether the ministry could publicly name errant employers to assure people that action is being taken.
The ministry and the Tripartite Alliance for Fair and Progressive Employment Practices (Tafep) have publicised cases in situations of public interest or where the conduct is egregious, Mr Zaqy said.
"However, while naming all errant employers publicly would serve as a deterrence, there could be unintended consequences because we may end up indirectly identifying the affected employees or breaching their privacy," he said.
Tafep also develops case studies from actual cases and shares learning points with employers through briefings and workshops, he added.
It publishes the numbers and main types of complaints it receives in its annual reports.
MOM and Tafep received an average of 450 complaints a year about unfair employment practices from 2015 to 2017, Mr Zaqy said.
Most were about favouritism towards foreigners or discrimination based on age, he said.
When Tafep investigates complaints, employers are generally cooperative. But those who are uncooperative or found to have unfair employment practices may have their work-pass privileges curtailed, he said.
Most of the complaints arise because employers do not have a proper system to address internal grievances or are insensitive to the different needs and conditions of employees, Mr Zaqy also said. The aim is to help these employers improve their internal practices or resolve the complaints amicably.
Mr Patrick Tay (West Coast GRC) suggested publicising the industries and sizes of companies involved in complaints. Mr Zaqy said the MOM would consider doing so.