There is a system forbidding discrimination of working conditions, welfare benefits, displinary punishment and dismissal, etc. It is prescribed in LABOR STANDARD ACTS and ACT ON THE EMPLOYMENT, ETC. OF FOREIGN WORKERS and so on.
As a foreigner worker, discrimination on the basis of NATIONALITY could be a problem.
NATIONALITY is a position based on NATIONALITY ACT and different from the word “race” using as a biological and anthropological approach.
In principle, Labor law like LABOR STANDARD ACT is also, even applied to illegal employed foreigners who violate IMMIGRATION ACT