When the rule-making authority delegates to itself or to some other subordinate authority a further power to issue rules, such exercise of rule-making power is known as sub-delegated legislation.
Rule-making authority cannot delegate power unless such power of delegation is contained in the enabling act. Such authorization may be either express or by necessary implication.
Maxim ‘delegatus non potest delegare’ indicates that sub-delegation of power is normally not allowable, though the legislature can always provide for it.
If the authority further delegates its law-making power to some other authority and retains a general control of a substantial nature over it, there is no delegation as to attract the doctrine of ‘delegatus non potest delegare.’
The maxim was originally invoked in the context of delegation of judicial powers and implied that in the entire process of adjudication, a judge must act personally except in so far as he is expressly absolved from his duty by a statute.
Sub-delegation in very wide language is improper and some safeguard must be provided before the delegate is allowed to sub-delegate his power.