Q: I hired employees, but did not state in the contract that they are entitled to the legally required employee benefits. Am I required to provide these benefits because of dina d’malchusa?
A: According to many authorities, dina d’malchusa applies to laws that are for the social welfare of society. Others maintain that it does not apply to laws between individuals, against Torah law, even when for social welfare (Rema, C.M. 369:11; Shach 73:39).
Nonetheless, even according to those situations in which dina d’malchusa does not apply, it often generates a common commercial practice. On contractual issues, such as those between employer and employee, buyer and seller, or landlord and renter, it is not feasible to stipulate everything. Therefore, the common commercial practice is binding in these areas, whenever not stipulated otherwise (C.M. 330:1; Shach 356:10).
The Poskim give great weight to the common practice in employer/employee relations. In most situation, employee rights rooted in civil law also become the common practice, so that they are halachically binding and you must provide them (Pischei Choshen, Sechirus 10:36; Igros Moshe C.M. 1:72).