The Supreme Court in K.K. Velusamy vs N. Palaanisamy 2011 (11) SCC 275 held as under:-
The scope of section 151 has been explained by this Court in several decisions (See : Padam Sen vs. State of UP-AIR 1961 SC 218; Manoharlal Chopra vs. Seth Hiralal - AIR 1962 SC 527; Arjun Singh vs. Mohindra Kumar - AIR 1964 SC 993; Ram Chand and Sons Sugar Mills (P) Ltd. vs. Kanhay Lal - AIR 1966 SC 1899; Nain Singh vs. Koonwarjee - 1970 (1) SCC 732; The Newabganj Sugar Mills Co.Ltd. vs. Union of India - AIR 1976 SC 1152; Jaipur Mineral Development Syndicate vs. Commissioner of Income Tax, New Delhi - AIR 1977 SC 1348; National Institute of Mental Health & Neuro Sciences vs. C Parameshwara - 2005 (2) SCC 256; and Vinod Seth vs. Devinder Bajaj - 2010 (8) SCC 1). We may summarize them as follows:
(a) Section 151 is not a substantive provision which creates or confers any power or jurisdiction on courts. It merely recognizes the discretionary power inherent in every court as a necessary corollary for rendering justice in accordance with law, to do what is right' and undo what iswrong', that is, to do all things necessary to secure the ends of justice and prevent abuse of its process.
(b) As the provisions of the Code are not exhaustive, section 151 recognizes and confirms that if the Code does not expressly or impliedly cover any particular procedural aspect, the inherent power can be used to deal with such situation or aspect, if the ends of justice warrant it. The breadth of such power is co-extensive with the need to exercise such power on the facts and circumstances.
(c) A Court has no power to do that which is prohibited by law or the Code, by purported exercise of its inherent powers. If the Code contains provisions dealing with a particular topic or aspect, and such provisions either expressly or necessary implication exhaust the scope of the power of the court or the jurisdiction that may exercised in relation to that matter, the inherent power cannot be invoked in order to cut across the powers conferred by the Code or a manner inconsistent with such provisions. In other words the court cannot make use of the special provisions of Section 151 of the Code, where the remedy or procedure is provided in the Code.
(d) The inherent powers of the court being complementary to the powers specifically conferred, a court is free to exercise them for the purposes mentioned in Section 151 of the Code when the matter is not covered by any specific provision in the Code and the exercise of those powers would not in any way be in conflict with what has been expressly provided in the Code or be against the intention of the Legislature.
(e) While exercising the inherent power, the court will be doubly cautious, as there is no legislative guidance to deal with the procedural situation and the exercise of power depends upon the discretion and wisdom of the court, and the facts and circumstances of the case. The absence of an express provision in the code and the recognition and saving of the inherent power of a court, should not however be treated as a carte blanche to grant any relief.
(f) The power under section 151 will have to be used with circumspection and care, only where it is absolutely necessary, when there is no provision in the Code governing the matter, when the bona fides of the applicant cannot be doubted, when such exercise is to meet the ends of justice and to prevent abuse of process of court.
The Apex Court further held:-
The need for the court to act in a manner to achieve the ends of justice (subject to the need to comply with the law) does not end when arguments are heard and judgment is reserved. If there is abuse of the process of the court, or if interests of justice require the court to do something or take note of something, the discretion to do those things does not disappear merely because the arguments are heard, either fully or partly. The convention that no application should be entertained once the trial or hearing is concluded and the case is reserved for judgment is a sound rule, but not a straitjacket formula. There can always be exceptions in exceptional or extra-ordinary circumstances, to meet the ends of justice and to prevent abuse of process of court, subject to the limitation recognized with reference to exercise of power under section 151 of the Code.
Supreme Court also clarified that-
The power under section 151 or Order 18 Rule 17 of the Code is not intended to be used routinely, merely for the asking. If so used, it will defeat the very purpose of various amendments to the Code to expedite trials. But where the application is found to be bona fide and where the additional evidence, oral or documentary, will assist the court to clarify the evidence on the issues and will assist in rendering justice, and the court is satisfied that non-production earlier was for valid and sufficient reasons, the court may exercise its discretion to recall the witnesses or permit the fresh evidence. But if it does so, it should ensure that the process does not become a protracting tactic. The court should firstly award appropriate costs to the other party to compensate for the delay. Secondly the court should take up and complete the case within a fixed time schedule so that the delay is avoided. Thirdly if the application is found to be mischievous, or frivolous, or to cover up negligence or lacunae, it should be rejected with heavy costs.