Reasons for delegated legislation
Lack of parliamentary time: parliament has insufficient time to legislate on all matters be they national or otherwise. By delegating some of its law-making authority, parliament can save time to solve much more pressing problems.
Speed the procedure of law making in parliament is slow and parliament is not always in session to cope with any emergency or urgent problem that may arise. The alternative to dealing with such a situation is to delegate some powers to a competent authority.
Technicality of subject matter: sometimes the proposed legislation is so technical in nature that it demands an expert to handle it. Since parliament is essentially a general body, rather than a body of experts, such legislation can best be dealt with a minister assisted experts in the area of the proposed legislation.
Flexibility: Law making parliament is field to rigid provisions of the constitution and the National Assembly Standing Orders, and if a situation arise which necessitates the immediate repeal or amendment of an Act, it has to be effected through this procedure.