The sole legitimate authority for making substantive law rests with the legislature, which authority shall not be delegated to any other entity.
The separation of powers doctrine, part of the Rule of Law, requires that each branch of government concern itself exclusively with its own sphere of competence. This ensures the accountability of the legislature for its law-making programme, for which there exists the democratic sanction. The legislature alone is responsible for substantive law-making because it lacks the authority to defer that authority to any other institution.
ELEMENTS OF THE IMPERATIVE
Legitimacy of the legislature – The legislature is the legitimate law-making body because, being democratically elected, it is composed of the representatives of the people who are bound by the laws that it enacts.
Substantive law – Substantive laws are those laws which regulate the conduct of the citizens. These must be distinguished from regulations, which serve only the purpose of facilitating the implementation of already-created substantive law. Regulations cannot supplant substantive law, and substantive law may not be incorporated into regulations.
Delegation – Delegation is the act of assigning a function of one organ of state to another, or to a private body. This usually happens vertically from principals to subordinates, but has increasingly happened between the branches of government. This violates the doctrine of the separation of powers. The legislature may not legally delegate its law-making function to the executive or to any other institution.
Section 43 of the Constitution.